Communication method, mobile station apparatus, base station apparatus and mobile communication system

ABSTRACT

In case that a base station apparatus and a mobile station apparatus use a plurality of component carriers to communicate with each other, they effectively transmit and receive HARQ control information. At least one physical downlink control channel on at least a first downlink component carrier attempts to be decoded, and, in case that one physical downlink control channel corresponding to one physical downlink shared channel transmission on a second downlink component carrier other than the first downlink component carrier is detected, the HARQ control information is transmitted to the base station apparatus using a first physical uplink control channel resource whereas, in case that one physical downlink control channel corresponding to one physical downlink shared channel transmission on the first downlink component carrier is detected, the HARQ control information is transmitted to the base station apparatus using a second physical uplink control channel resource.

TECHNICAL FIELD

The present invention relates to a mobile communication system includinga base station apparatus and a mobile station apparatus and to acommunication method.

BACKGROUND ART

The 3rd generation partnership project (3GPP) is a project thatdiscusses and prepares specifications of a mobile communication systembased on a network evolved from Wideband-Code Division Multiple Access(W-CDMA) and Global System for Mobile Communications (GSM). In the 3GPP,the W-CDMA system is standardized as a third generation cellular mobilecommunication system, and services are sequentially launched. Moreover,High-speed Downlink Packet Access (HSDPA) having a higher communicationspeed is also standardized, and its service is launched. In the 3GPP, astudy is in progress on the evolution of a third generation radio accesstechnology (hereinafter referred to as “Long Term Evolution (LTE)” or“Evolved Universal Terrestrial Radio Access (EUTRA)”) and on a mobilecommunication system realizing a higher-speed data transmission andreception by use of a wider frequency band (hereinafter referred to as“Long Term Evolution-Advanced (LTE-A)” or “Advanced-EUTRA”).

As the communication system in the LTE, an examination is beingperformed on an Orthogonal Frequency Division Multiple Access (OFDMA)method in which subcarriers orthogonal to each other are used to performuser multiplexing and an Single Carrier-Frequency Division MultipleAccess (SC-FDMA) method. That is, in a downlink, the OFDMA method, whichis a multicarrier communication method, is proposed, and in an uplink,the SC-FDMA method, which is a single carrier communication method, isproposed.

On the other hand, as the communication system in the LTE-A, anexamination is being performed, in a downlink, on the OFDMA method and,in an uplink, on the introduction of a Clustered-SingleCarrier-Frequency Division Multiple Access (clustered-SC-FDMA, alsoreferred to as a DFT-s-OFDM with spectrum division control or aDFT-precoded OFDM) in addition to the SC-FDMA method. Here, the SC-FDMAmethod and the clustered-SC-FDMA method, which are proposed as theuplink communication method in the LTE and the LTE-A, are characterizedin that, due to the characteristic of a single carrier communicationmethod (due to a single carrier characteristic), it is possible tosuppress low a Peak to Average Power Ratio (PAPR: a transmit power) whendata (information) is transmitted.

Although a frequency band used in a general mobile communication systemis contiguous, in the LTE-A, it is considered to compositely use aplurality of contiguous and/or non-contiguous frequency bands(hereinafter referred to as a “Component Carrier (CC)” or a “CarrierComponent (CC)”), to operate the frequency bands as one frequency band(a wide frequency band) (Frequency band aggregation: also referred to asCarrier aggregation, Spectrum aggregation, Frequency aggregation or thelike). Furthermore, it is also proposed that, in order for a basestation apparatus and a mobile station apparatus to use a wide frequencyband more flexibly to communicate with each other, a frequency band usedin a downlink communication is made to differ in frequency bandwidthfrom a frequency band used in an uplink communication (Asymmetricfrequency band aggregation: Asymmetric carrier aggregation) (non-patentdocument 1).

FIG. 9 is a diagram illustrating a carrier-aggregated mobilecommunication system in a conventional technology. That, as shown inFIG. 9, a frequency band used in a downlink (DL) communication and afrequency used in an uplink (UL) communication have the same bandwidthis also referred to as Symmetric frequency band aggregation. As shown inFIG. 9, a base station apparatus and a mobile station apparatuscompositely use a plurality of component carriers that are contiguousand/or non-contiguous frequency bands, and thus they can communicatewith each other in a wide frequency band composed of a plurality ofcomponent carriers. FIG. 9 shows as an example that a frequency band(also referred to as a DL system band or a DL system bandwidth) used ina downlink communication having a bandwidth of 100 MHz is composed offive downlink component carriers (DCC1: Downlink Component Carrier 1,DCC2, DCC3, DCC4 and DCC5) each having a bandwidth of 20 MHz. FIG. 9also shows as an example that a frequency band (also referred to as a ULsystem band or a UL system bandwidth) used in an uplink communicationhaving a bandwidth of 100 MHz is composed of five uplink componentcarriers (UCC1: Uplink Component Carrier 1, UCC2, UCC3, UCC4 and UCC5)each having a bandwidth of 20 MHz.

As shown in FIG. 9, on each of the downlink component carriers, downlinkchannels such as a Physical Downlink Control Channel (PDCCH) and aPhysical Downlink Shared Channel (PDSCH) are mapped. The base stationapparatus allocates, to the mobile station apparatus using the PDCCH,control information (such as resource allocation information, Modulationand Coding Scheme (MCS) information, Hybrid Automatic Repeat Request(HARQ) processing information for transmitting a downlink transportblock that is transmitted using the PDSCH, and transmits, using thePDSCH, the downlink transport block to the mobile station apparatus. Inother words, in FIG. 9, the base station apparatus can transmit up tofive downlink transport blocks to the mobile station apparatus in thesame sub-frame.

On each of the uplink component carriers, uplink channels such as aPhysical Uplink Control Channel (PUCCH) and a Physical Uplink SharedChannel (PUSCH) are mapped. The mobile station apparatus uses the PUCCHand/or the PUSCH to transmit, to the base station apparatus, UplinkControl Information (UCI) such as control information of the HARQ(hereinafter described as HARQ control information), channel stateinformation and a scheduling request. Here, the HARQ control informationincludes information that indicates Positive Acknowledgment/NegativeAcknowledgment (ACK/NACK, ACK or NACK) for the PDCCH and/or the downlinktransport block and/or information that indicates DiscontinuousTransmission (DTX). The information indicating the DTX is informationwhich indicates that the mobile station apparatus has failed to detectthe PDCCH transmitted from the base station apparatus.

Here, in FIG. 9, downlink/uplink component carriers where any one of thedownlink/uplink channels such as the PDCCH, the PDSCH, the PUCCH and thePUSCH is not mapped may be present.

Likewise, FIG. 10 is a diagram illustrating an asymmetricallycarrier-aggregated mobile communication system in the conventionaltechnology. As shown in FIG. 10, in a base station apparatus and amobile station apparatus, a frequency band used in a downlinkcommunication differs in bandwidth from a frequency band used in anuplink communication, and the base station apparatus and the mobilestation apparatus compositely use component carriers that are contiguousand/or non-contiguous frequency bands constituting these frequency bandsand can communicate with each other in a wide frequency band. FIG. 10shows as an example that a frequency band used in a downlinkcommunication having a bandwidth of 100 MHz is composed of five downlinkcomponent carriers (DCC1, DCC2, DCC3, DCC4 and DCC5) each having abandwidth of 20 MHz. FIG. 10 also shows that a frequency band used in anuplink communication having a bandwidth of 40 MHz is composed of twouplink component carriers (UCC1 and UCC2) each having a bandwidth of 20MHz.

In FIG. 10, on each of the downlink/uplink component carriers, adownlink/uplink channel is mapped, and the base station apparatus usesthe PDCCH to allocate the PDSCH to the mobile station apparatus, anduses the PDSCH to transmit the downlink transport block to the mobilestation apparatus. In other words, in FIG. 10, the base stationapparatus can transmit up to five downlink transport blocks to themobile station apparatus in the same sub-frame. Moreover, the mobilestation apparatus uses the PUCCH and/or the PUSCH to transmit, to thebase station apparatus, uplink control information such as the HARQcontrol information, the channel state information and the schedulingrequest.

In the LTE-A, an allocation method is proposed in which the base stationapparatus uses the PDCCH on the downlink component carrier to allocatethe PDSCH to the mobile station apparatus (non-patent document 2).

FIG. 11 is a diagram illustrating an example of the method of using thePDCCH to allocate the PDSCH in the conventional technology. FIG. 11shows part (part of DCC1, DCC2 and DCC3) of the downlink componentcarrier in FIGS. 9 and 10. As shown in FIG. 11, the base stationapparatus uses a plurality of PDCCHs on one downlink component carrier,and thereby can allocate a plurality of PDSCHs to the mobile stationapparatus in the same sub-frame.

FIG. 11 shows as an example that the base station apparatus uses threePDCCHs (PDCCHs respectively indicated by oblique lines, grid lines andmesh lines) on DCC2, to allocate PDSCHs on DCC1, DCC2 and DCC3 (thePDSCH on DCC1 is allocated by the PDCCH indicated by the oblique lines,the PDSCH on DCC2 is allocated by the PDCCH indicated by the grid linesand the PDSCH on DCC3 is allocated by the PDCCH indicated by the meshlines). The base station apparatus uses the PDSCHs on DCC1, DCC2 andDCC3, and thereby can transmit up to three downlink transport blocks tothe mobile station apparatus in the same sub-frame.

-   Non-patent document 1: “Carrier aggregation in LTE-Advanced”, 3GPP    TSG RAN WG1 Meeting #53bis, R1-082468, Jun. 30-Jul. 4, 2008.-   Non-patent document 2: “PDCCH Design of Carrier Aggregation”, 3GPP    TSG RAN WG1 Meeting #57, R1-091829, May 4-8, 2009.

DISCLOSURE OF THE INVENTION

However, in the conventional technology, when the base station apparatusand the mobile station apparatus transmit and receive the HARQ controlinformation, they disadvantageously use radio resources inefficiently.

The present invention is made in view of the foregoing conditions andhas an object to provide a communication method, a mobile stationapparatus, a base station apparatus and a mobile communication system inwhich, in case that the base station apparatus and the mobile stationapparatus compositely use component carriers to communicate with eachother in a wide frequency band, they can use radio resources efficientlyto transmit and receive the HARQ control information.

(1) To achieve the above object, the present invention takes thefollowing measures. That is, the communication method of the presentinvention is a communication method of a mobile station apparatus thatuses a plurality of component carriers to communicate with a basestation apparatus, and includes the steps of: attempting to decode aphysical downlink control channel transmitted by the base stationapparatus on a first downlink component carrier; transmitting controlinformation of a HARQ to the base station apparatus using a firstphysical uplink control channel resource, in case that one physicaldownlink control channel corresponding to transmission of one physicaldownlink shared channel on a second downlink component carrier otherthan the first downlink component carrier is detected; and transmittingthe control information of the HARQ to the base station apparatus usinga second physical uplink control channel resource, in case that onephysical downlink control channel corresponding to transmission of onephysical downlink shared channel on the first downlink component carrieris detected.

(2) In the communication method of the present invention, in case that aplurality of physical downlink control channels corresponding totransmission of a plurality of physical downlink shared channels isdetected, the control information of the HARQ is transmitted to the basestation apparatus using the first physical uplink control channelresource.

(3) The communication method of the present invention is a communicationmethod of a mobile station apparatus that uses a plurality of componentcarriers to communicate with a base station apparatus, comprising thesteps of: attempting to decode a physical downlink control channeltransmitted by the base station apparatus on a first downlink componentcarrier; transmitting control information of a HARQ to the base stationapparatus using a first transmission format, in case that one physicaldownlink control channel corresponding to transmission of one physicaldownlink shared channel on a second downlink component carrier otherthan the first downlink component carrier is detected; and transmittingthe control information of the HARQ to the base station apparatus usinga second transmission format, in case that one physical downlink controlchannel corresponding to transmission of one physical downlink sharedchannel on the first downlink component carrier is detected.

(4) In the communication method of the present invention, in case that aplurality of physical downlink control channels corresponding totransmission of a plurality of physical downlink shared channels isdetected, the control information of the HARQ is transmitted to the basestation apparatus using the first transmission format.

(5) In the communication method of the present invention, the firstdownlink component carrier is indicated by the base station apparatususing a RRC signal.

(6) In the communication method of the present invention, the firstdownlink component carrier is a downlink component carrier correspondingto an uplink component carrier on which the mobile station apparatustransmits the control information of the HARQ using a physical uplinkcontrol channel.

(7) In the communication method of the present invention, the firstdownlink component carrier is a downlink component carrier on which themobile station apparatus performs initial connection establishment tothe base station apparatus.

(8) In the communication method of the present invention, the controlinformation of the HARQ includes information indicating ACK/NACK for adownlink transport block.

(9) In the communication method of the present invention, the controlinformation of the HARQ includes information indicating DiscontinuousTransmission (DTX).

(10) In the communication method of the present invention, a physicalresource block used as the first physical uplink control channelresource is specified by the base station apparatus.

(11) In the communication method of the present invention, a resourceused as the first physical uplink control channel resource is identifiedby an orthogonal sequence specified by the base station apparatus.

(12) In the communication method of the present invention, a physicalresource block used as the second physical uplink control channelresource is specified by the base station apparatus.

(13) In the communication method of the present invention, a resourceused as the second physical uplink control channel resource isidentified by an orthogonal sequence and a cyclic shift specified by thebase station apparatus.

(14) In the communication method of the present invention, the number ofinformation bits that can be transmitted using the first transmissionformat in each sub-frame is more than the number of information bitsthat can be transmitted using the second transmission format in eachsub-frame.

(15) In the communication method of the present invention, in the firsttransmission format, a modulation scheme having a higher modulationlevel than a modulation scheme used in the second transmission formatcan be used.

(16) In the communication method of the present invention, a physicalresource block used for the first transmission format is specified bythe base station apparatus.

(17) In the communication method of the present invention, a resourceused for the first transmission format is identified by an orthogonalsequence specified by the base station apparatus.

(18) In the communication method of the present invention, a physicalresource block used for the second transmission format is specified bythe base station apparatus.

(19) In the communication method of the present invention, a resourceused for the second transmission format is identified by an orthogonalsequence and a cyclic shift specified by the base station apparatus.

(20) In the communication method of the present invention, the firsttransmission format is a transmission format capable of simultaneouslytransmitting the control information of the HARQ and channel stateinformation.

(21) In the communication method of the present invention, the firsttransmission format is a transmission format capable of simultaneouslytransmitting the control information of the HARQ and a schedulingrequest.

(22) The communication method of the present invention is acommunication method of a base station apparatus that uses a pluralityof component carriers to communicate with a mobile station apparatus,and includes the steps of: transmitting, on a first downlink componentcarrier, a physical downlink control channel to the mobile stationapparatus; receiving control information of a HARQ from the mobilestation apparatus using a first physical uplink control channelresource, in case that the mobile station apparatus detects one physicaldownlink control channel corresponding to transmission of one physicaldownlink shared channel on a second downlink component carrier otherthan the first downlink component carrier; and receiving the controlinformation of the HARQ from the mobile station apparatus using a secondphysical uplink control channel resource, in case that the mobilestation apparatus detects one physical downlink control channelcorresponding to transmission of one physical downlink shared channel onthe first downlink component carrier.

(23) In the communication method of the present invention, in case thatthe mobile station apparatus detects a plurality of physical downlinkcontrol channels corresponding to transmission of a plurality ofphysical downlink shared channels, the control information of the HARQis received from the mobile station apparatus using the first physicaluplink control channel resource.

(24) The communication method of the present invention is acommunication method of a base station apparatus that uses a pluralityof component carriers to communicate with a mobile station apparatus,comprising the steps of: transmitting, on a first downlink componentcarrier, a physical downlink control channel to the mobile stationapparatus; receiving control information of a HARQ from the mobilestation apparatus using a first transmission format, incase that themobile station apparatus detects one physical downlink control channelcorresponding to transmission of one physical downlink shared channel ona second downlink component carrier other than the first downlinkcomponent carrier; and receiving the control information of the HARQfrom the mobile station apparatus using a second transmission format, incase that the mobile station apparatus detects one physical downlinkcontrol channel corresponding to transmission of one physical downlinkshared channel on the first downlink component carrier.

(25) In the communication method of the present invention, in case thatthe mobile station apparatus detects a plurality of physical downlinkcontrol channels corresponding to transmission of a plurality ofphysical downlink shared channels, the control information of the HARQis received from the mobile station apparatus using the firsttransmission format.

(26) In the communication method of the present invention, the firstdownlink component carrier is indicated to the mobile station apparatus,using a RRC signal.

(27) In the communication method of the present invention, the firstdownlink component carrier is a downlink component carrier correspondingto an uplink component carrier on which the mobile station apparatustransmits the control information of the HARQ using a physical uplinkcontrol channel.

(28) In the communication method of the present invention, the firstdownlink component carrier is a downlink component carrier on which themobile station apparatus performs initial connection establishment tothe base station apparatus.

(29) In the communication method of the present invention, the controlinformation of the HARQ includes information indicating ACK/NACK for adownlink transport block.

(30) In the communication method of the present invention, the controlinformation of the HARQ includes information indicating DiscontinuousTransmission (DTX).

(31) In the communication method of the present invention, a physicalresource block used as the first physical uplink control channelresource is specified to the mobile station apparatus.

(32) In the communication method of the present invention, a resourceused as the first physical uplink control channel resource is identifiedby an orthogonal sequence specified to the mobile station apparatus.

(33) In the communication method of the present invention, a physicalresource block used as the second physical uplink control channelresource is specified to the mobile station apparatus.

(34) In the communication method of the present invention, a resourceused as the second physical uplink control channel resource isidentified by an orthogonal sequence and a cyclic shift specified to themobile station apparatus.

(35) In the communication method of the present invention, the number ofinformation bits that can be transmitted using the first transmissionformat in each sub-frame is more than the number of information bitsthat can be transmitted using the second transmission format in eachsub-frame.

(36) In the communication method of the present invention, in the firsttransmission format, a modulation scheme having a higher modulationlevel than a modulation scheme used in the second transmission formatcan be used.

(37) In the communication method of the present invention, a physicalresource block used for the first transmission format is specified tothe mobile station apparatus.

(38) In the communication method of the present invention, a resourceused for the first transmission format is identified by an orthogonalsequence specified to the mobile station apparatus.

(39) In the communication method of the present invention, a physicalresource block used for the second transmission format is specified tothe mobile station apparatus.

(40) In the communication method of the present invention, a resourceused for the second transmission format is identified by an orthogonalsequence and a cyclic shift specified to the mobile station apparatus.

(41) In the communication method of the present invention, the firsttransmission format is a transmission format with which the mobilestation apparatus can simultaneously transmit the control information ofthe HARQ and channel state information.

(42) In the communication method of the present invention, the firsttransmission format is a transmission format with which the mobilestation apparatus can simultaneously transmit the control information ofthe HARQ and a scheduling request.

(43) The mobile station apparatus of the present invention is a mobilestation apparatus that uses a plurality of component carriers tocommunicate with a base station apparatus, wherein the mobile stationapparatus: attempts to decode a physical downlink control channeltransmitted by the base station apparatus on a first downlink componentcarrier; transmits control information of a HARQ to the base stationapparatus using a first physical uplink control channel resource, incase that one physical downlink control channel corresponding totransmission of one physical downlink shared channel on a seconddownlink component carrier other than the first downlink componentcarrier is detected; and transmits the control information of the HARQto the base station apparatus using a second physical uplink controlchannel resource, in case that one physical downlink control channelcorresponding to transmission of one physical downlink shared channel onthe first downlink component carrier is detected.

(44) The mobile station apparatus of the present invention is a mobilestation apparatus that uses a plurality of component carriers tocommunicate with a base station apparatus, wherein the mobile stationapparatus: attempts to decode a physical downlink control channeltransmitted by the base station apparatus on a first downlink componentcarrier; transmits control information of a HARQ to the base stationapparatus using a first transmission format, in case that one physicaldownlink control channel corresponding to transmission of one physicaldownlink shared channel on a second downlink component carrier otherthan the first downlink component carrier is detected; and transmits thecontrol information of the HARQ to the base station apparatus using asecond transmission format, in case that one physical downlink controlchannel corresponding to transmission of one physical downlink sharedchannel on the first downlink component carrier is detected.

(45) The base station apparatus of the present invention is a basestation apparatus that uses a plurality of component carriers tocommunicate with a mobile station apparatus, wherein the base stationapparatus: transmits, on a first downlink component carrier, a physicaldownlink control channel to the mobile station apparatus; receivescontrol information of a HARQ from the mobile station apparatus using afirst physical uplink control channel resource, in case that the mobilestation apparatus detects one physical downlink control channelcorresponding to transmission of one physical downlink shared channel ona second downlink component carrier other than the first downlinkcomponent carrier; and receives the control information of the HARQ fromthe mobile station apparatus using a second physical uplink controlchannel resource, in case that the mobile station apparatus detects onephysical downlink control channel corresponding to transmission of onephysical downlink shared channel on the first downlink componentcarrier.

(46) The base station apparatus of the present invention is a basestation apparatus that uses a plurality of component carriers tocommunicate with a mobile station apparatus, wherein the base stationapparatus: transmits, on a first downlink component carrier, a physicaldownlink control channel to the mobile station apparatus; receivescontrol information of a HARQ from the mobile station apparatus using afirst transmission format, in case that the mobile station apparatusdetects one physical downlink control channel corresponding totransmission of one physical downlink shared channel on a seconddownlink component carrier other than the first downlink componentcarrier; and receives the control information of the HARQ from themobile station apparatus using a second transmission format, in casethat the mobile station apparatus detects one physical downlink controlchannel corresponding to transmission of one physical downlink sharedchannel on the first downlink component carrier.

(47) The mobile communication system of the present invention is amobile communication system in which a base station apparatus and amobile station apparatus use a plurality of component carriers tocommunicate with each other, wherein the base station apparatustransmits, on a first downlink component carrier, a physical downlinkcontrol channel to the mobile station apparatus, and wherein the mobilestation apparatus transmits control information of a HARQ to the basestation apparatus using a first physical uplink control channelresource, in case that one physical downlink control channelcorresponding to transmission of one physical downlink shared channel ona second downlink component carrier other than the first downlinkcomponent carrier is detected, and transmits the control information ofthe HARQ to the base station apparatus using a second physical uplinkcontrol channel resource, in case that one physical downlink controlchannel corresponding to transmission of one physical downlink sharedchannel on the first downlink component carrier is detected.

(48) The mobile communication system of the present invention is amobile communication system in which a base station apparatus and amobile station apparatus use a plurality of component carriers tocommunicate with each other, wherein the base station apparatustransmits, on a first downlink component carrier, a physical downlinkcontrol channel to the mobile station apparatus, and wherein the mobilestation apparatus transmits control information of a HARQ to the basestation apparatus using a first transmission format, in case that onephysical downlink control channel corresponding to transmission of onephysical downlink shared channel on a second downlink component carrierother than the first downlink component carrier is detected, andtransmits the control information of the HARQ to the base stationapparatus using a second transmission format, in case that one physicaldownlink control channel corresponding to transmission of one physicaldownlink shared channel on the first downlink component carrier isdetected.

According to the present invention, in case that the base stationapparatus and the mobile station apparatus compositely use componentcarriers to communicate with each other in a wide frequency band, theycan use radio resources efficiently to transmit and receive the HARQcontrol information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram conceptually showing the configuration of a physicalchannel according to an embodiment of the present invention;

FIG. 2 is a block diagram schematically showing the configuration of abase station apparatus according to the embodiment of the presentinvention;

FIG. 3 is a block diagram schematically showing the configuration of amobile station apparatus according to the embodiment of the presentinvention;

FIG. 4 is a diagram showing an example of a mobile communication systemto which a first embodiment and a second embodiment can be applied;

FIG. 5 is a diagram showing an example of the configuration of anorthogonal resource in a physical uplink control channel;

FIG. 6 is a diagram showing another example of the configuration of theorthogonal resource in the physical uplink control channel;

FIG. 7 is a diagram showing another example of the configuration of theorthogonal resource in the physical uplink control channel;

FIG. 8 is a diagram showing an example of a mobile communication systemto which a third embodiment and a fourth embodiment can be applied;

FIG. 9 is a diagram showing an example of frequency band aggregation ina conventional technology;

FIG. 10 is a diagram showing an example of asymmetric frequency bandaggregation in the conventional technology; and

FIG. 11 is a diagram showing an example of a method of using a physicaldownlink control channel to allocate a physical downlink shared channelin the conventional technology.

BEST MODES FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will now be described withreference to accompanying drawings. FIG. 1 is a diagram showing anexample of the configuration of channels according to an embodiment ofthe present invention. A downlink physical channel is composed of aPhysical Broadcast Channel (PBCH), a Physical Downlink Control Channel(PDCCH), a Physical Downlink Shared Channel (PDSCH), a PhysicalMulticast Channel (PMCH), a Physical Control Format Indicator Channel(PCFICH) and a Physical Hybrid ARQ Indicator Channel (PHICH). An uplinkphysical channel is composed of a Physical Uplink Shared Channel(PUSCH), a Physical Uplink Control Channel (PUCCH) and a Physical RandomAccess Channel (PRACH).

The PBCH maps the Broadcast Channel (BCH) at intervals of 40milliseconds. The timing of 40 milliseconds is detected by blinddetection. In other words, explicit signaling is not performed topresent timing. With respect to a sub-frame including the PBCH, decodingcan be performed with only the sub-frame (self-decodable).

The PDCCH is a channel that is used to provide, to the mobile stationapparatus, notification (specification) of the resource allocation ofthe PDSCH, HARQ processing information on downlink data, the resourceallocation of the PUSCH and the like. The PDCCH is composed of aplurality of Control Channel Elements (CCEs); the mobile stationapparatus detects the PDCCH composed of the CCEs and thereby receivesthe PDCCH from the base station apparatus. The CCE includes a pluralityof Resource Element Groups (REGs, also referred to as mini-CCEs) spreadin a frequency domain and a time domain. Here, the resource element is aunit resource that is composed of one OFDM symbol (time component) andone sub-carrier (frequency component); for example, the REG is composedof four downlink resource elements contiguous in a frequency domainwithin the same OFDM symbol except a downlink pilot channel. Forexample, one PDCCH is composed of one, two, four or eight CCEs in whichnumbers (CCE indices) for identifying the CCEs are continuous.

Here, the PDCCHs are separately coded on an individual mobile stationapparatus basis for each type (separate coding). That is, the mobilestation apparatus detects a plurality of PDCCHs, and acquires resourceallocation in a downlink or an uplink and other control information. Avalue of Circulation Redundancy Check (CRC) is given to each of thePDCCHs; the mobile station apparatus performs the CRC on each of thesets of CCEs that are likely to constitute the PDCCH, and thereby canacquire the PDCCH in which the CRC has been successfully performed. Thisis also referred to as blind decoding; a range of the sets of CCEs thatare likely to constitute the PDCCH and that are subjected to the blinddecoding is referred to as a search space. In other words, the mobilestation apparatus performs the blind decoding on the CCEs within thesearch space and detects the PDCCH.

In case that the resource allocation of the PDSCH is transmitted on thePDCCH, the mobile station apparatus responds to the resource allocationindicated by the PDCCH from the base station apparatus, and uses thePDSCH to receive data (hereinafter also referred to as a downlinksignal) (downlink data (Downlink Shared Channel (DL-SCH) and/or downlinkcontrol data (downlink control information)). In other words, this PDCCHis a signal (hereinafter also referred to as a “downlink transmissionpermission signal” or a “downlink grant”) for performing the resourceallocation for the downlink. In case that the resource allocation of thePUSCH is transmitted on the PDCCH, the mobile station apparatus respondsto the resource allocation indicated by the PDCCH from the base stationapparatus, and uses the PUSCH to transmit data (hereinafter alsoreferred to as an uplink signal) (uplink data (Uplink Shared Channel(UL-SCH) and/or uplink control data (uplink control information)). Inother words, this PDCCH is a signal (hereinafter also referred to as an“uplink transmission permission signal” or an “uplink grant”) forpermitting the data transmission for the uplink.

The PDSCH is a channel that is used for transmitting downlink data(Downlink Shared Channel: DL-SCH) or paging information (Paging Channel:PCH). The PMCH is a channel that is utilized for transmitting aMulticast Channel (MCH); a downlink reference signal, an uplinkreference signal and a physical downlink synchronization signal areadditionally mapped.

Here, the downlink data (DL-SCH) indicates, for example, thetransmission of user data, and the DL-SCH is a transport channel. In theDL-SCH, the HARQ and dynamic adaptive radio link control are supported,and beam forming is available. In the DL-SCH, dynamic resourceallocation and quasi-static resource allocation are supported.

The PUSCH is a channel that is mainly used for transmitting the uplinkdata (Uplink Shared Channel: UL-SCH). When the base station apparatusperforms scheduling on the mobile station apparatus, the uplink controlinformation is also transmitted using the PUSCH. The uplink controlinformation composed of the Channel State Information (CSI) (or ChannelStatistical Information) that indicates the channel state of thedownlink, a downlink channel quality indicator (CQI), a precoding matrixindicator (PMI), a rank indicator (RI) and the HARQ control information.Here, the HARQ control information includes information that indicatesACK/NACK for the PDCCH and/or the downlink transport block transmittedfrom the base station apparatus and/or information that indicates theDTX. The information indicating the DTX refers to information whichindicates that the mobile station apparatus has failed to detect thePDCCH transmitted from the base station apparatus.

Here, the uplink data (UL-SCH) indicates, for example, the transmissionof user data, and the UL-SCH is a transport channel. In the UL-SCH, theHARQ and dynamic adaptive radio link control are supported, and beamforming is available. In the UL-SCH, dynamic resource allocation andquasi-static resource allocation are supported.

The uplink data (UL-SCH) and the downlink data (DL-SCH) may include aRadio Resource Control Signaling (hereinafter referred to as a “RRCsignaling”) exchanged between the base station apparatus and the mobilestation apparatus, a Medium Access Control (MAC) control element and thelike. The base station apparatus and the mobile station apparatustransmit and receive the RRC signaling in a higher layer (a radioresource control layer). The base station apparatus and the mobilestation apparatus also transmit and receive the MAC control element in ahigher layer (a Medium Access Control (MAC) layer).

The PUCCH is a channel that is used for transmitting the uplink controlinformation. Here, the uplink control information includes, for example,the channel state information (CSI) indicating the downlink channelstate, the downlink channel quality indicator (CQI), the precodingmatrix indicator (PMI), the rank indicator (RI), the Scheduling Request(SR) in which the mobile station apparatus requests resource allocationfor transmitting the uplink data (requests the transmission in theUL-SCH) and the HARQ control information.

The PCFICH is a channel that is utilized for notifying the mobilestation apparatus of the number of OFDM symbols used for the PDCCH, andthe PCFICH is transmitted in each sub-frame. The PHICH is a channel thatis utilized for transmitting ACK/NACK of the HARQ for the uplink data(UL-SCH). The PRACH is a channel that is used for transmitting a randomaccess preamble, and the PRACH has a guard time. As shown in FIG. 1, themobile communication system according to the present embodiment includesthe base station apparatus 100 and mobile station apparatuses 200.

[Configuration of the Base Station Apparatus 100]

FIG. 2 is a block diagram schematically showing the configuration of thebase station apparatus 100 according to the embodiment of the presentinvention. The base station apparatus 100 is configured to include adata control unit 101, a transmission data modulation unit 102, a radiounit 103, a scheduling unit 104, a channel estimation unit 105, areceived data demodulation unit 106, a data extraction unit 107, ahigher layer 108 and an antenna 109. The radio unit 103, the schedulingunit 104, the channel estimation unit 105, the received datademodulation unit 106, the data extraction unit 107, the higher layer108 and the antenna 109 constitute a reception unit; the data controlunit 101, the transmission data modulation unit 102, the radio unit 103,the scheduling unit 104, the higher layer 108 and the antenna 109constitute a transmission unit.

The antenna 109, the radio unit 103, the channel estimation unit 105,the received data demodulation unit 106 and the data extraction unit 107perform processing on the uplink physical layer. The antenna 109, theradio unit 103, the transmission data modulation unit 102 and the datacontrol unit 101 perform processing on the downlink physical layer.

The data control unit 101 receives the transport channel from thescheduling unit 104. The data control unit 101 maps, on the physicalchannel, the transport channel and a signal and a channel generated inthe physical layer based on scheduling information input from thescheduling unit 104. Each piece of data mapped as described above isoutput to the transmission data modulation unit 102.

The transmission data modulation unit 102 modulates the transmissiondata into the OFDM system. Based on the scheduling information from thescheduling unit 104 and a modulation scheme and a coding methodcorresponding to each PRB, the transmission data modulation unit 102performs, on the data input from the data control unit 101, datamodulation, coding, series/parallel transform on the input signal,Inverse Fast Fourier Transform (IFFT) processing, Cyclic Prefix (CP)insertion and signal processing such as filtering, generatestransmission data and outputs it to the radio unit 103. Here, thescheduling information includes downlink physical resource blockPhysical Resource Block (PRB) allocation information, for example,physical resource block position information including a frequency and atime; the modulation scheme and the coding method corresponding to eachPRB includes, for example, information such as the modulation scheme: 16QAM and a coding rate: 2/3.

The radio unit 103 upconverts the modulation data input from thetransmission data modulation unit 102 into a radio frequency to generatea radio signal, and transmits it through the antenna 109 to the mobilestation apparatus 200. The radio unit 103 receives the uplink radiosignal from the mobile station apparatus 200 through the antenna 109,downconverts it into a base band signal and outputs the received data tothe channel estimation unit 105 and the received data demodulation unit106.

The scheduling unit 104 performs processing on the Medium Access Control(MAC) layer. The scheduling unit 104 performs mapping on a logicalchannel and the transport channel, scheduling (such as HARQ processingand the selection of a transport format) for the downlink and the uplinkand the like. The scheduling unit 104 has, in order to integrallycontrol the processing units of individual physical layers, interfacesbetween the scheduling unit 104 and the antenna 109, the radio unit 103,the channel estimation unit 105, the received data demodulation unit106, the data control unit 101, the transmission data modulation unit102 and the data extraction unit 107 (not shown).

In the downlink scheduling, based on feedback information (the uplinkchannel state information (CSI, CQI, PMI and RI) received from themobile station apparatus 200, the ACK/NACK information on the downlinkdata and the like), information on the PRB available in each of themobile station apparatuses 200, buffer conditions, the schedulinginformation input from the higher layer 108 and the like, the schedulingunit 104 performs selection processing on the downlink transport format(the transmission form, that is, the allocation of the physical resourceblock, the modulation scheme, the coding method and the like) formodulating each piece of data, retransmission control on the HARQ andthe generation of scheduling information that is used for the downlink.The scheduling information used for scheduling the downlink is output tothe data control unit 101.

In the uplink scheduling, based on the result of estimation of theuplink channel state (radio propagation path state) output by thechannel estimation unit 105, a resource allocation request from themobile station apparatus 200, the information on the PRB available ineach of the mobile station apparatuses 200, the scheduling informationinput from the higher layer 108 and the like, the scheduling unit 104performs selection processing on the uplink transport format (thetransmission form, that is, the allocation of the physical resourceblock, the modulation scheme, the coding method and the like) formodulating each piece of data and the generation of schedulinginformation that is used for the uplink scheduling. The schedulinginformation used for scheduling the uplink is output to the data controlunit 101.

The scheduling unit 104 maps the downlink logical channel input from thehigher layer 108 on the transport channel, and outputs it to the datacontrol unit 101. The scheduling unit 104 also processes, as necessary,the control data input from the data extraction unit 107 and acquired inthe uplink and the transport channel, thereafter maps them on the uplinklogical channel and outputs it to the higher layer 108.

In order to demodulate the uplink data, the channel estimation unit 105estimates the uplink channel state from an uplink Demodulation ReferenceSignal (DRS), and outputs the result of the estimation to the receiveddata demodulation unit 106. Moreover, in order to perform uplinkscheduling, the channel estimation unit 105 estimates the uplink channelstate from an uplink Sounding Reference Signal (SRS) and outputs theresult of the estimation to the scheduling unit 104.

The received data demodulation unit 106 also functions as an OFDMdemodulation unit and/or a DFT-spread-OFDM (DFT-S-OFDM) demodulationunit that demodulate the received data modulated into the OFDM systemand/or the SC-FDMA system, respectively. Based on the result of theestimation of the uplink channel state input from the channel estimationunit 105, the received data demodulation unit 106 performs, on themodulation data input from the radio unit 103, signal processing such asDFT transport, sub-carrier mapping, IFFT transport and filtering, andthereby performs demodulation processing, and outputs it to the dataextraction unit 107.

The data extraction unit 107 checks whether the data input from thereceived data demodulation unit 106 is right or wrong, and outputs theresult of the checking (positive acknowledgment signal ACK/negativeacknowledgment signal NACK) to the scheduling unit 104. The dataextraction unit 107 also separates the transport channel and the controldata on the physical layer from the data input from the received datademodulation unit 106, and outputs them to the scheduling unit 104. Theseparated control data includes the channel state information (CSI)notified from the mobile station apparatus 200, the downlink channelquality indicator (CQI), the precoding matrix indicator (PMI), the rankindicator (RI), the HARQ control information, the scheduling request andthe like.

The higher layer 108 performs processing on a Packet Data ConvergenceProtocol (PDCP) layer, a Radio Link Control (RLC) layer and a RadioResource Control (RRC) layer. The higher layer 108 has, in order tointegrally control the processing units of the lower layer, interfacesbetween the higher layer 108 and the scheduling unit 104, the antenna109, the radio unit 103, the channel estimation unit 105, the receiveddata demodulation unit 106, the data control unit 101, the transmissiondata modulation unit 102 and the data extraction unit 107 (not shown).

The higher layer 108 includes a radio resource control unit 110 (alsoreferred to as a control unit). The radio resource control unit 110performs management on various types of setting information, managementon system information, paging control, management on the communicationstate of each of the mobile station apparatuses 200, mobility managementsuch as handover and the like, management on the buffer conditions ofeach of the mobile station apparatuses 200, management on the connectionsettings of a unicast and a multicast bearer, management on a mobilestation indicator (UEID) and the like. The higher layer 108 exchangesinformation with another base station apparatus 100 and information withan higher node.

[Configuration of the Mobile Station Apparatus 200]

FIG. 3 is a block diagram schematically showing the configuration of themobile station apparatus 200 according to the embodiment of the presentinvention. The mobile station apparatus 200 is configured to include adata control unit 201, a transmission data modulation unit 202, a radiounit 203, a scheduling unit 204, a channel estimation unit 205, areceived data demodulation unit 206, a data extraction unit 207, ahigher layer 208 and an antenna 209. The data control unit 201, thetransmission data modulation unit 202, the radio unit 203, thescheduling unit 204, the higher layer 208 and the antenna 209 constitutea transmission unit; the radio unit 203, the scheduling unit 204, thechannel estimation unit 205, the received data demodulation unit 206,the data extraction unit 207, the higher layer 208 and the antenna 209constitute a reception unit.

The data control unit 201, the transmission data modulation unit 202 andthe radio unit 203 perform processing on the uplink physical layer. Theradio unit 203, the channel estimation unit 205, the received datademodulation unit 206 and the data extraction unit 207 performprocessing on the downlink physical layer.

The data control unit 201 receives the transport channel from thescheduling unit 204. The data control unit 201 maps, on the physicalchannel, the transport channel and a signal and a channel generated inthe physical layer based on scheduling information input from thescheduling unit 204. Each piece of data mapped in this way is output tothe transmission data modulation unit 202.

The transmission data modulation unit 202 modulates the transmissiondata into the OFDM system and/or the SC-FDMA system. The transmissiondata modulation unit 202 performs, on the data input from the datacontrol unit 201, data modulation, Discrete Fourier Transform (DFT)processing, sub-carrier mapping, Inverse Fast Fourier Transform (IFFT)processing, CP insertion and signal processing such as filtering,generates transmission data and outputs it to the radio unit 203.

The radio unit 203 upconverts the modulation data input from thetransmission data modulation unit 202 into a radio frequency to generatea radio signal and transmits it through the antenna 209 to the basestation apparatus 100. The radio unit 203 receives the radio signalmodulated with the downlink data from the base station apparatus 100through the antenna 209, downconverts it into a base band signal andoutputs the received data to the channel estimation unit 205 and thereceived data demodulation unit 206.

The scheduling unit 204 performs processing on the Medium Access Control(MAC) layer. The scheduling unit 204 performs mapping on a logicalchannel and the transport channel, scheduling (such as HARQ processingand the selection of a transport format) for the downlink and the uplinkand the like. The scheduling unit 204 has, in order to integrallycontrol the processing units of individual physical layers, interfacesbetween the scheduling unit 204 and the antenna 209, the data controlunit 201, the transmission data modulation unit 202, the channelestimation unit 205, the received data demodulation unit 206, the dataextraction unit 207 and the radio unit 203 (not shown).

In the downlink scheduling, based on scheduling information (such as thetransport format and HARQ retransmission information) from the basestation apparatus 100 and the higher layer 208 and the like, thescheduling unit 204 performs reception control on the transport channel,the physical signal and the physical channel and HARQ retransmissioncontrol and the generation of the scheduling information used for thedownlink scheduling. The scheduling information used for the downlinkscheduling is output to the data control unit 201.

In the uplink scheduling, based on uplink buffer conditions input fromthe higher layer 208, uplink scheduling information (such as thetransport format and HARQ retransmission information) from the basestation apparatus 100 that is input from the data extraction unit 207,scheduling information input from the higher layer 208, the schedulingunit 204 performs scheduling processing for mapping the uplink logicalchannel input from the higher layer 208 on the transport channel and thegeneration of the scheduling information used for uplink scheduling. Forthe uplink transport format, the information notified from the basestation apparatus 100 is utilized. The scheduling information describedabove is output to the data control unit 201.

The scheduling unit 204 maps the uplink logical channel input from thehigher layer 208 on the transport channel, and outputs it to the datacontrol unit 201. The scheduling unit 204 also outputs, to the datacontrol unit 201, the downlink channel state information (CSI) inputfrom the channel estimation unit 205, the downlink channel qualityindicator (CQI), the precoding matrix indicator (PMI), the rankindicator (RI) and the result of checking of the CRC check input fromthe data extraction unit 207. The scheduling unit 204 also processes, asnecessary, the control data input from the data extraction unit 207 andacquired in the downlink and the transport channel, thereafter maps themon the downlink logical channel and outputs it to the higher layer 208.

In order to demodulate the downlink data, the channel estimation unit205 estimates the downlink channel state from a downlink ReferenceSignal (RS), and outputs the result of the estimation to the receiveddata demodulation unit 206. Moreover, in order to notify the basestation apparatus 100 of the result of the estimation of the downlinkchannel state (radio propagation path state), the channel estimationunit 205 estimates the downlink channel state from the downlinkReference Signal (RS) and outputs the result of the estimation to thescheduling unit 204 as the downlink channel state information CSI, thedownlink channel quality indicator CQI, the precoding matrix indicatorPMI and the rank indicator RI.

The received data demodulation unit 206 demodulates the received datamodulated into the OFDM system. Based on the result of the estimation ofthe downlink channel state input from the channel estimation unit 205,the received data demodulation unit 206 performs demodulation processingon the modulation data input from the radio unit 203, and outputs it tothe data extraction unit 207.

The data extraction unit 207 performs the CRC check on the data inputfrom the received data demodulation unit 206 to check whether it isright or wrong, and outputs the result of the checking (positiveacknowledgment ACK/negative acknowledgment NACK) to the scheduling unit204. The data extraction unit 207 also separates the transport channeland the control data on the physical layer from the data input from thereceived data demodulation unit 206, and outputs them to the schedulingunit 204. The separated control data includes scheduling informationsuch as the resource allocation in the downlink or the uplink and theuplink HARQ control information.

The higher layer 208 performs processing on a Packet Data ConvergenceProtocol (PDCP) layer, a Radio Link Control (RLC) layer and a RadioResource Control (RRC) layer. The higher layer 208 has, in order tointegrally control the processing units of the lower layer, interfacesbetween the higher layer 208 and the scheduling unit 204, the antenna209, the data control unit 201, the transmission data modulation unit202, the channel estimation unit 205, the received data demodulationunit 206, the data extraction unit 207 and the radio unit 203 (notshown).

The higher layer 208 includes a radio resource control unit 210 (alsoreferred to as a control unit). The radio resource control unit 210performs management on various types of setting information, managementon system information, paging control, management on the communicationstate of the own station, mobility management such as handover,management on the buffer conditions, management on the connectionsettings of a unicast and a multicast bearer and management on a mobilestation indicator (UEID).

First Embodiment

A first embodiment in the mobile communication system using the basestation apparatus 100 and the mobile station apparatus 200 will now bedescribed. In the first embodiment, the base station apparatus 100transmits, to the mobile station apparatus 200, a first parameterspecifying a first region where the mobile station apparatus 200 canutilize the PUCCH and transmits, to the mobile station apparatus 200, asecond parameter specifying a second region that is different from thefirst region where the mobile station apparatus 200 can utilize thePUCCH; in case that the base station apparatus 100 uses a plurality ofPDCCHs to allocate (schedule) a plurality of PDSCHs in the samesub-frame, the mobile station apparatus 200 uses the first region totransmit the HARQ control information to the base station apparatus 100whereas, in case that the base station apparatus 100 uses one PDCCH toallocate (schedule) one PDSCH, the mobile station apparatus 200 uses thefirst region or the second region to transmit the HARQ controlinformation to the base station apparatus 100.

The base station apparatus 100 transmits, to the mobile stationapparatus 200, the first parameter specifying the first region where themobile station apparatus 200 can utilize the PUCCH and transmits, to themobile station apparatus 200, the second parameter specifying the secondregion that is different from the first region where the mobile stationapparatus 200 can utilize the PUCCH; in case that the base stationapparatus 100 uses one PDCCH on a component carrier other than aspecific component carrier to allocate (schedule) one PDSCH, the mobilestation apparatus 200 uses the first region to transmit the HARQ controlinformation to the base station apparatus 100 whereas, in case that thebase station apparatus 100 uses one PDCCH on the specific componentcarrier to allocate (schedule) one PDSCH, the mobile station apparatus200 uses the second region to transmit the HARQ control information tothe base station apparatus 100.

The base station apparatus 100 transmits, to the mobile stationapparatus 200, the first parameter specifying the first region where themobile station apparatus 200 can utilize the PUCCH and transmits, to themobile station apparatus 200, the second parameter specifying the secondregion that is different from the first region where the mobile stationapparatus 200 can utilize the PUCCH; in case that the base stationapparatus 100 uses a plurality of PDCCHs to allocate (schedule) aplurality of PDSCHs in the same sub-frame or in case that the basestation apparatus 100 uses one PDCCH on a component carrier other thanthe specific component carrier to allocate (schedule) one PDSCH, themobile station apparatus 200 uses the first region to transmit the HARQcontrol information to the base station apparatus 100 whereas, in casethat the base station apparatus 100 uses one PDCCH on the specificcomponent carrier to allocate (schedule) one PDSCH, the mobile stationapparatus 200 uses the second region to transmit the HARQ controlinformation to the base station apparatus 100.

Furthermore, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize a first transmissionformat, and transmits, to the mobile station apparatus 200, the secondparameter specifying the second region in which the mobile stationapparatus 200 can utilize a second transmission format and which isdifferent from the first region; in case that the base station apparatus100 uses a plurality of PDCCHs to allocate (schedule) a plurality ofPDSCHs in the same sub-frame, the mobile station apparatus 200 uses thefirst transmission format to transmit the HARQ control information tothe base station apparatus 100 whereas, in case that the base stationapparatus 100 uses one PDCCH to allocate (schedule) one PDSCH, themobile station apparatus 200 uses the first transmission format or thesecond transmission format to transmit the HARQ control information tothe base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,the second parameter specifying the second region in which the mobilestation apparatus 200 can utilize the second transmission format andwhich is different from the first region; in case that the base stationapparatus 100 uses one PDCCH on a component carrier other than thespecific component carrier to allocate (schedule) one PDSCH, the mobilestation apparatus 200 uses the first transmission format to transmit theHARQ control information to the base station apparatus 100 whereas, incase that the base station apparatus 100 uses one PDCCH on the specificcomponent carrier to allocate (schedule) one PDSCH, the mobile stationapparatus 200 uses the second transmission format to transmit the HARQcontrol information to the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,the second parameter specifying the second region in which the mobilestation apparatus 200 can utilize the second transmission format andwhich is different from the first region; in case that the base stationapparatus 100 uses a plurality of PDCCHs to allocate (schedule) aplurality of PDSCHs in the same sub-frame or in case that the basestation apparatus 100 uses one PDCCH on a component carrier other thanthe specific component carrier to allocate (schedule) one PDSCH, themobile station apparatus 200 uses the first transmission format totransmit the HARQ control information to the base station apparatus 100whereas, in case that the base station apparatus 100 uses one PDCCH onthe specific component carrier to allocate (schedule) one PDSCH, themobile station apparatus 200 uses the second transmission format totransmit the HARQ control information to the base station apparatus 100.

Here, the HARQ control information transmitted from the mobile stationapparatus 200 includes information indicating ACK/NACK and/orinformation indicating the DTX for the PDCCH and/or the downlinktransport block transmitted from the base station apparatus 100. Theinformation indicating the DTX is information which indicates that themobile station apparatus 200 has failed to detect the PDCCH transmittedfrom the base station apparatus 100.

The first parameter transmitted from the base station apparatus 100 tothe mobile station apparatus 200 includes information indicating abandwidth (bandwidth of a PUCCH resource region) that specifies thefirst region where the mobile station apparatus 200 can utilize thePUCCH. The first parameter also includes information (which isinformation on the orthogonal resource or may be information forcalculating the orthogonal resource) indicating the orthogonal resourcethat specifies the first region where the mobile station apparatus 200can utilize the PUCCH. The first parameter also includes informationindicating a bandwidth (bandwidth of the PUCCH resource region) wherethe mobile station apparatus 200 can utilize the first transmissionformat. The first parameter also includes information (which isinformation on the orthogonal resource or may be information forcalculating the orthogonal resource) indicating the orthogonal resourcewhere the mobile station apparatus 200 can utilize the firsttransmission format.

Furthermore, the second parameter transmitted from the base stationapparatus 100 to the mobile station apparatus 200 includes informationindicating a bandwidth (bandwidth of the PUCCH resource region) thatspecifies the second region where the mobile station apparatus 200 canutilize the PUCCH. The second parameter also includes information (whichis information on the orthogonal resource or may be information forcalculating the orthogonal resource) indicating the orthogonal resourcethat specifies the second region where the mobile station apparatus 200can utilize the PUCCH. The second parameter also includes informationindicating a bandwidth (bandwidth of the PUCCH resource region) wherethe mobile station apparatus 200 can utilize the second transmissionformat. The second parameter also includes information (which isinformation on the orthogonal resource or may be information forcalculating the orthogonal resource) indicating the orthogonal resourcewhere the mobile station apparatus 200 can utilize the secondtransmission format.

Although, in the following description of the present embodiment, thefrequency band is defined by the bandwidth (Hz), it may be defined bythe number of resource blocks (RBs) including frequencies and times. Inother words, the bandwidth may be defined by the number of resourceblocks. The bandwidth and the number of resource blocks can be alsodefined by the number of sub-carriers. The component carrier in thepresent embodiment refers to a (narrow) frequency band that iscompositely used when the base station apparatus 100 and the mobilestation apparatus 200 communicate with each other in a mobilecommunication system having a (wide) frequency band (which may be asystem band). The base station apparatus 100 and the mobile stationapparatus 200 aggregate a plurality of component carriers (for example,five frequency bands each having a bandwidth of 20 MHz), and therebyconstitute a (wide) frequency band (for example, a frequency band havinga bandwidth of 100 MHz); these component carriers are compositely used,and thus it is possible to realize a high-speed data communication (thetransmission and reception of information).

The component carrier indicates each of the (narrow) frequency bands(for example, a frequency band having a bandwidth of 20 MHz) thatconstitute this (wide) frequency band (for example, a frequency bandhaving a bandwidth of 100 MHz). The component carrier may indicate a(center) carrier frequency of each of the (narrow) frequency bands.Specifically, the downlink component carrier has a band (width) of thefrequency band that can be used when the base station apparatus 100 andthe mobile station apparatus 200 transmit and receives downlinkinformation; the uplink component carrier has a band (width) of thefrequency band that can be used when the base station apparatus 100 andthe mobile station apparatus 200 transmit and receives uplinkinformation. Furthermore, the component carrier may be defined as a unitin which a specific physical channel (for example, the PDCCH or thePUCCH) is configured.

The component carriers may be mapped either in contiguous frequencybands or in non-contiguous frequency bands; the base station apparatus100 and the mobile station apparatus 200 aggregate a plurality ofcomponent carriers that are contiguous and/or non-contiguous frequencybands, to constitute a wide frequency band; these component carriers arecompositely used, and thus it is possible to realize a high-speed datacommunication (the transmission and reception of information).

Furthermore, a frequency band that is composed of the component carriersand that is used in the downlink communication and a frequency band thatis used in the uplink communication do not need to have the samebandwidth; the base station apparatus 100 and the mobile stationapparatus 200 compositely use a downlink frequency band that is composedof the component carriers and that has a different bandwidth and anuplink frequency band, and thereby can communicate with each other (theasymmetric carrier aggregation described above).

FIG. 4 is a diagram showing an example of a mobile communication systemto which the first embodiment can be applied. FIG. 4 shows an enlargedpart of FIG. 9 and FIG. 10 for ease of illustration of the firstembodiment. That is, the first embodiment can be applied to any of thesymmetrically carrier-aggregated and asymmetrically carrier-aggregatedmobile communication systems. In the following description, as anexample, only component carriers in the enlarged part will be discussed;needless to say, the same embodiment can be applied to all the componentcarriers.

FIG. 4 shows, as an example of the description of the first embodiment,three downlink component carriers (DCC1, DCC2 and DCC3). FIG. 4 alsoshows three uplink component carriers (UCC1, DCC2 and UCC3).

In FIG. 4, the base station apparatus 100 uses (one or a plurality of)PDCCHs on the downlink component carriers, and allocates (schedules)(one or a plurality of) PDSCHs in the same sub-frame. Here, the basestation apparatus 100 cannot allocate, with one PDCCH, a plurality ofPDSCHs in the same sub-frame.

The base station apparatus 100 can allocate the PDSCH on the samecomponent carrier as the component carrier where the PDCCH is mapped.FIG. 4 shows as an example with a solid line that the base stationapparatus 100 uses the PDCCH (PDCCH indicated by oblique lines) on DCC1to allocate the PDSCH on DCC1. FIG. 4 also shows with a solid line thatthe base station apparatus 100 uses the PDCCH (PDCCH indicated by gridlines) on DCC2 to allocate the PDSCH on DCC2. FIG. 4 also shows with asolid line that the base station apparatus 100 uses the PDCCH (PDCCHindicated by mesh lines) on DCC3 to allocate the PDSCH on DCC3.

In FIG. 4, the base station apparatus 100 can allocate the PDSCH whichis on a component carrier that is the same as or different from thecomponent carrier where the PDCCH is mapped. For example, the basestation apparatus 100 transmits, to the mobile station apparatus 200, acomponent Carrier Indicator Field (CIF; for example, an informationfield represented by three bits) on the PDCCH, and thereby can allocatethe PDSCH on a component carrier that is the same as or different fromthe component carrier where the PDCCH is mapped. In other words, thebase station apparatus 100 transmits, on the PDCCH, the componentcarrier indicator field indicating the component carrier where the PDSCHallocated using the PDCCH is mapped, transmits it and allocates, to themobile station apparatus 200, the PDSCH on the component carrier that isthe same as or different from the component carrier where the PDCCH ismapped.

Here, what value is indicated by a component carrier indicator fieldtransmitted from the base station apparatus 100 and that the PDSCH onwhich corresponding component carrier is accordingly allocated arepreviously specified, and this is known information between the basestation apparatus 100 and the mobile station apparatus 200.

For example, the base station apparatus 100 transmits, on the PDCCH, acomponent carrier indicator field indicating a specific value (forexample, an information field represented by three bits indicates“000”), transmits it to the mobile station apparatus 200 and therebyallocates, to the mobile station apparatus 200, the PDSCH on the samecomponent carrier as the component carrier where the PDCCH is mapped.The base station apparatus 100 transmits, on the PDCCH, a componentcarrier indicator field indicating a value other than the specific value(for example, an information field represented by three bits indicates avalue other than “000”), transmits it and thereby allocates, to themobile station apparatus 200, the PDSCH on a component carrier differentfrom the component carrier where the PDCCH is mapped.

FIG. 4 shows as an example with a dotted line that the base stationapparatus 100 uses the PDCCH (PDCCH indicated by oblique lines) on DCC1to allocate the PDSCH on DCC2. FIG. 4 also shows with a dotted line thatthe base station apparatus 100 uses the PDCCH (PDCCH indicated by gridlines) on DCC2 to allocate the PDSCH on DCC1. FIG. 4 also shows with adotted line that the base station apparatus 100 uses the PDCCH (PDCCHindicated by mesh lines) on DCC3 to allocate the PDSCH on DCC3.

Furthermore, the base station apparatus 100 can set, for each of themobile station apparatuses 200, information indicating whether or notthe component carrier indicator field is transmitted on the PDCCH. Forexample, the base station apparatus 100 includes, in the RRC signaling,information indicating whether or not the component carrier indicatorfield is transmitted on the PDCCH, and sets the information to themobile station apparatus 200. The base station apparatus 100 also canset, for each of the component carriers, information indicating whetheror not the component carrier indicator field is transmitted on thePDCCH. For example, the base station apparatus 100 includes, for each ofthe component carriers, in the RRC signaling, information indicatingwhether or not the component carrier indicator field is transmitted onthe PDCCH, and sets the information to the mobile station apparatus 200.

In FIG. 4, the base station apparatus 100 uses the PDSCH allocated usingthe PDCCH to transmit the downlink transport block to the mobile stationapparatus 200. For example, the base station apparatus 100 uses thePDSCHs allocated using the PDCCHs respectively on DCC1, DCC2 and DCC3 totransmit, to the mobile station apparatus 200, downlink transport blocks(up to three and corresponding to the number of downlink componentcarriers) in the same sub-frame.

Here, the base station apparatus 100 can set, specific to a cell, thecorrespondence (link: linkage) between the downlink component carrierand the uplink component carrier. For example, the base stationapparatus 100 can use broadcast information (broadcast channel) to setthe correspondence between the downlink component carrier and the uplinkcomponent carrier to the mobile station apparatus 200. Moreover, thebase station apparatus 100 can set, specific to the mobile stationapparatus, the correspondence between the downlink component carrier andthe uplink component carrier. For example, the base station apparatus100 can use the RRC signaling to set the correspondence between thedownlink component carrier and the uplink component carrier to themobile station apparatus 200.

In FIG. 4, the mobile station apparatus 200 uses the PUSCH allocatedusing the PDCCH (which may be the uplink transmission permission signal)transmitted from the base station apparatus 100 to transmit the uplinktransport block to the base station apparatus 100. For example, themobile station apparatus 200 uses the PUSCHs on UCC1, UCC2 and UCC3 totransmit, to the base station apparatus 100, uplink transport blocks (upto three and corresponding to the number of uplink component carriers)in the same sub-frame.

In FIG. 4, the mobile station apparatus 200 uses the PUCCH to transmit,to the base station apparatus 100, the HARQ control information for thePDCCH and/or the downlink transport block transmitted from the basestation apparatus 100.

Here, the base station apparatus 100 can set the uplink componentcarrier for the mobile station apparatus 200 to transmit the HARQcontrol information. For example, the base station apparatus 100 usesthe RRC signaling to set, to the mobile station apparatus 200, oneuplink component carrier for the mobile station apparatus 200 totransmit the HARQ control information. FIG. 4 shows, as an example, thatthe base station apparatus 100 sets UCC2 as the uplink component carrierfor the mobile station apparatus 200 to transmit the HARQ controlinformation. The mobile station apparatus 200 uses the PUCCH on UCC2 setby the base station apparatus 100 to transmit the HARQ controlinformation.

In FIG. 4, a region that is extended with a dotted line from the PUCCH(PUCCH resource region indicated by a dotted pattern) on UCC2conceptually shows the PUCCH on UCC2 Here, for ease of illustration, ahorizontal direction is assumed to be a frequency resource (which may berepresented as a bandwidth), and an orthogonal resource described lateris not illustrated.

In FIG. 4, the base station apparatus 100 transmits the first parameterspecifying the first region (region B indicated by RB3 to RB5) where themobile station apparatus 200 can utilize the PUCCH. In other words, thebase station apparatus 100 can specify, from the PUCCH resource regionon UCC2, the first region for the mobile station apparatus 200 totransmit the HARQ control information. For example, the base stationapparatus 100 transmits, using the RRC signaling, the first parameter,and thereby specifies the first region specific to the mobile stationapparatus. Moreover, for example, the base station apparatus 100transmits, using the broadcast channel, the first parameter, and therebyspecifies the first region specific to the cell.

For example, the base station apparatus 100 transmits, as the firstparameter, the bandwidth of the PUCCH resource, and thereby specifiesthe first region. Moreover, for example, the base station apparatus 100transmits, as the first parameter, information indicating the orthogonalresource described later, and thereby specifies the first region. Here,the base station apparatus 100 may also notify (set), as the firstparameter, a starting position for the first region, and thereby specifythe first region. Moreover, the mobile station apparatus 200 may receivethe first parameter from the base station apparatus 100, and therebyrecognize region A (region A represented by RB1 and RB2).

In FIG. 4, the base station apparatus 100 transmits the second parameterspecifying the second region (region C indicated by RB6 to RB8) wherethe mobile station apparatus 200 can utilize the PUCCH. In other words,the base station apparatus 100 can specify, from the PUCCH resourceregion, the second region for the mobile station apparatus 200 totransmit the HARQ control information. For example, the base stationapparatus 100 transmits, using the RRC signaling, the second parameter,and thereby specifies the second region specific to the mobile stationapparatus. Moreover, for example, the base station apparatus 100transmits, using the broadcast channel, the second parameter, andthereby specifies the second region specific to the cell.

For example, the base station apparatus 100 transmits, as the secondparameter, the bandwidth of the PUCCH resource, and thereby specifiesthe second region. Moreover, for example, the base station apparatus 100transmits, as the second parameter, information indicating theorthogonal resource described later, and thereby specifies the secondregion. Here, the base station apparatus 100 may notify (set), as thesecond parameter, a starting position for the second region, and therebyspecify the second region.

For example, in FIG. 4, the base station apparatus 100 can transmit,using the RCC signaling, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the PUCCH, to themobile station apparatus 200, and can transmit, using the broadcastchannel, the second parameter specifying the second region where themobile station apparatus 200 can utilize the PUCCH, to the mobilestation apparatus 200. The base station apparatus 100 transmits thefirst parameter and the second parameter in this way, and thus it ispossible to set, for each of the mobile station apparatuses 200, thefirst region where the mobile station apparatus 200 can utilize thePUCCH and set, for each of the cells, the second region where the mobilestation apparatus 200 can utilize the PUCCH.

Furthermore, in FIG. 4, the base station apparatus 100 can allocate,using the RRC signaling, the PUCCH for the mobile station apparatus 200to transmit the HARQ control information. In other words, the basestation apparatus 100 can use the RRC signaling to indicate which PUCCHwithin each of the first region and the second region specified for themobile station apparatus 200 is used to transmit the HARQ controlinformation.

Moreover, the base station apparatus 100 can allocate the PUCCH for themobile station apparatus 200 to transmit the HARQ control information inassociation with the PDCCH. In other words, the base station apparatus100 can indicate which PUCCH within each of the first region and thesecond region specified for the mobile station apparatus 200 is used totransmit the HARQ control information in association with the PDCCH.

For example, the base station apparatus 100 can, depending on a positionin the PDCCH resource region of the PDCCH on the downlink componentcarrier, indicate which PUCCH within each of the first region and thesecond region the mobile station apparatus 200 uses to transmit the HARQcontrol information. In other words, the mobile station apparatus 200maps, based on how the PDCCH transmitted from the base station apparatus100 is mapped in the PDCCH resource region, the HARQ control informationon the PUCCH within each of the first region and the second region, andtransmits it to the base station apparatus 100. Here, the correspondencebetween the PDCCH transmitted from the base station apparatus 100 andthe PUCCH within each of the first region and the second region isspecified by associating a CCE index which is a head of the CCEsconstituting the PDCCH with the index of the PUCCH within each of thefirst region and the second region.

In FIG. 4, the mobile station apparatus 200 uses the PUCCH allocated bythe base station apparatus 100 to transmit the HARQ control informationto the base station apparatus 100.

Here, incase that the base station apparatus 100 uses a plurality ofPDCCHs to allocate a plurality of PDSCHs in the same sub-frame, themobile station apparatus 200 uses the first region to transmit the HARQcontrol information. Here, the mobile station apparatus 200 uses theregion A (region A represented by RB1 and RB2) to transmit, for example,the CSI or the CQI to the base station apparatus 100.

For example, in FIG. 4, in case that the base station apparatus 100 usesthe PDCCHs on DCC1, DCC2 and DCC3 respectively to allocate three PDSCHsin the same sub-frame, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information. For example, in casethat the base station apparatus 100 uses two PDCCHs on DCC2 to allocatetwo PDSCHs in the same sub-frame, the mobile station apparatus 200 usesthe first region to transmit the HARQ control information.

In FIG. 4, in case that the base station apparatus 100 uses one PDCCH toallocate one PDSCH, the mobile station apparatus 200 uses the firstregion or the second region to transmit the HARQ control information.

Here, incase that the base station apparatus 100 uses one PDCCH on acomponent carrier other than the specific component carrier to allocateone PDSCH, the mobile station apparatus 200 uses the first region totransmit the HARQ control information. In case that the base stationapparatus 100 uses one PDCCH on the specific component carrier toallocate one PDSCH, the mobile station apparatus 200 uses the secondregion to transmit the HARQ control information.

In FIG. 4, the base station apparatus 100 can set the specific downlinkcomponent carrier for the mobile station apparatus 200. For example, thebase station apparatus 100 uses the broadcast channel to set thespecific downlink component carrier for the mobile station apparatus200. For example, the base station apparatus 100 uses the RRC signalingto set the specific downlink component carrier for the mobile stationapparatus 200.

In other words, in case that the base station apparatus 100 uses onePDCCH on a component carrier other than the set specific downlinkcomponent carrier to allocate one PDSCH, the mobile station apparatus200 uses the first region to transmit the HARQ control information. Incase that the base station apparatus 100 uses one PDCCH on the setspecific downlink component carrier to allocate one PDSCH, the mobilestation apparatus 200 uses the second region to transmit the HARQcontrol information.

For example, in FIG. 4, in case that the base station apparatus 100 usesthe broadcast channel to set DCC2 as the specific downlink componentcarrier and uses one PDCCH on DCC1 or DCC3 to allocate one PDSCH, themobile station apparatus 200 uses the first region to transmit the HARQcontrol information. For example, in case that the base stationapparatus 100 uses the RRC signaling to set DCC2 as the specificdownlink component carrier and uses one PDCCH on DCC1 or DCC3 toallocate one PDSCH, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information.

For example, in case that the base station apparatus 100 uses thebroadcast channel to set DCC2 as the specific downlink component carrierand uses one PDCCH on DCC2 to allocate one PDSCH, the mobile stationapparatus 200 uses the second region to transmit the HARQ controlinformation. For example, in case that the base station apparatus 100uses the RRC signaling to set DCC2 as the specific downlink componentcarrier and uses one PDCCH on DCC2 to allocate one PDSCH, the mobilestation apparatus 200 uses the second region to transmit the HARQcontrol information.

Here, incase that the base station apparatus 100 uses a plurality ofPDCCHs on the specific downlink component carrier to allocate aplurality of PDSCHs in the same sub-frame, the mobile station apparatus200 uses the first region to transmit the HARQ control information.

In other words, the mobile station apparatus 200 uses the first regionto transmit, to the base station apparatus 100, the HARQ controlinformation for a plurality of PDCCHs and/or the downlink transportblock transmitted on a plurality of PDSCHs. The mobile station apparatus200 also uses the first region to transmit, to the base stationapparatus 100, the HARQ control information for one PDCCH on a componentcarrier other than the specific component carrier and/or the downlinktransport block transmitted on one PDSCH.

In other words, in case that the base station apparatus 100 uses aplurality of PDCCHs to allocate a plurality of PDSCHs in the samesub-frame or in case that the base station apparatus 100 uses one PDCCHon a component carrier other than the specific component carrier toallocate one PDSCH, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information.

The mobile station apparatus 200 uses the second region to transmit, tothe base station apparatus 100, the HARQ control information for onePDCCH on the specific component carrier and/or the downlink transportblock transmitted on one PDSCH.

Here, in FIG. 4, the base station apparatus 100 and the mobile stationapparatus 200 can recognize that the downlink component carriercorresponding to the uplink component carrier set, by the base stationapparatus 100, as the uplink component carrier on which the HARQ controlinformation is transmitted is the specific downlink component carrier.

In other words, in FIG. 4, in case that the base station apparatus 100uses the PDCCH on a component carrier other than the downlink componentcarrier corresponding to the uplink component carrier set as the uplinkcomponent carrier on which the HARQ control information is transmittedto allocate the PDSCH, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information. In case that the basestation apparatus 100 uses the PDCCH on the downlink component carriercorresponding to the uplink component carrier set as the uplinkcomponent carrier on which the HARQ control information is transmittedto allocate the PDSCH, the mobile station apparatus 200 uses the secondregion to transmit the HARQ control information.

For example, in FIG. 4, in case that the base station apparatus 100 usesthe broadcast channel to associate DCC2 with UCC2, and uses the PDCCH onDCC1 or DCC3 to allocate the PDSCH, the mobile station apparatus 200uses the first region to transmit the HARQ control information. Forexample, in case that the base station apparatus 100 uses the RRCsignaling to associate DCC2 with UCC2, and uses the PDCCH on DCC1 orDCC3 to allocate the PDSCH, the mobile station apparatus 200 uses thefirst region to transmit the HARQ control information.

For example, in case that the base station apparatus 100 uses thebroadcast channel to associate DCC2 with UCC2, and uses the PDCCH onDCC2 to allocate the PDSCH, the mobile station apparatus 200 uses thesecond region to transmit the HARQ control information. For example, incase that the base station apparatus 100 uses the RRC signaling toassociate DCC2 with UCC2, and uses the PDCCH on DCC2 to allocate thePDSCH, the mobile station apparatus 200 uses the second region totransmit the HARQ control information.

Here, as described above, in FIG. 4, the base station apparatus 100 setsUCC2 as the uplink component carrier on which the mobile stationapparatus 200 transmits the HARQ control information.

As described above, incase that the base station apparatus 100 uses aplurality of PDCCHs on the specific downlink component carrier toallocate a plurality of PDSCHs in the same sub-frame, the mobile stationapparatus 200 uses the first region to transmit the HARQ controlinformation.

Furthermore, in FIG. 4, the base station apparatus 100 and the mobilestation apparatus 200 can consider that a downlink component carrierused for performing the initial connection establishment is the specificdownlink component carrier. For example, the base station apparatus 100and the mobile station apparatus 200 can consider that a downlinkcomponent carrier used for performing a random access procedure is thespecific downlink component carrier.

In other words, in FIG. 4, in case that the base station apparatus 100uses the PDCCH on a component carrier other than the downlink componentcarrier used for performing the initial connection establishment toallocate the PDSCH, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information. In case that the basestation apparatus 100 uses the PDCCH on the downlink component carrierused for performing the initial connection establishment to allocate thePDSCH, the mobile station apparatus 200 uses the second region totransmit the HARQ control information.

For example, in FIG. 4, in case that the base station apparatus 100 usesthe PDCCH on DCC1 or DCC3 to allocate the PDSCH, the mobile stationapparatus 200 that performs, on DCC2, the initial connectionestablishment to the base station apparatus 100, uses the first regionto transmit the HARQ control information. For example, in case that thebase station apparatus 100 uses the PDCCH on DCC2 to allocate the PDSCH,the mobile station apparatus 200 that performs, on DCC2, the initialconnection establishment to the base station apparatus 100, uses thesecond region to transmit the HARQ control information.

Here, as described above, in case that the base station apparatus 100uses a plurality of PDCCHs on the specific downlink component carrier toallocate a plurality of PDCCHs in the same sub-frame, the mobile stationapparatus 200 uses the first region to transmit the HARQ controlinformation.

In FIG. 4, the mobile station apparatus 200, in case of transmitting theHARQ control information by using the first region, uses the firsttransmission format to transmit the HARQ control information to the basestation apparatus 100. In other words, the base station apparatus 100transmits, to the mobile station apparatus 200, the first parameterspecifying the first region where the mobile station apparatus 200 canutilize the first transmission format; the mobile station apparatus 200uses the first transmission format in the first region to transmit theHARQ control information to the base station apparatus 100.

Furthermore, the mobile station apparatus 200, in case of transmittingthe HARQ control information by using the second region, uses the secondtransmission format to transmit the HARQ control information to the basestation apparatus 100. In other words, the base station apparatus 100transmits, to the mobile station apparatus 200, the second parameterspecifying the second region where the mobile station apparatus 200 canutilize the second transmission format and which is different from thefirst region; the mobile station apparatus 200 uses the secondtransmission format in the second region to transmit the HARQ controlinformation to the base station apparatus 100.

In other words, in case that the base station apparatus 100 uses aplurality of PDCCHs to allocate a plurality of PDSCHs in the samesub-frame, the mobile station apparatus 200 uses the first transmissionformat to transmit the HARQ control information. In case that the basestation apparatus 100 uses one PDCCH to allocate one PDSCH, the mobilestation apparatus 200 uses the first transmission format or the secondtransmission format to transmit the HARQ control information.

In case that the base station apparatus 100 uses one PDCCH on acomponent carrier other than the specific component carrier to allocateone PDSCH, the mobile station apparatus 200 uses the first transmissionformat to transmit the HARQ control information. In other words, in casethat the base station apparatus 100 uses a plurality of PDCCHs toallocate a plurality of PDSCHs in the same sub-frame or in case that thebase station apparatus 100 uses one PDCCH on a component carrier otherthan the specific component carrier to allocate one PDSCH, the mobilestation apparatus 200 uses the first transmission format to transmit theHARQ control information.

In case that the base station apparatus 100 uses one PDCCH on thespecific component carrier to allocate one PDSCH, the mobile stationapparatus 200 uses the second transmission format to transmit the HARQcontrol information.

Here, the mobile station apparatus 200 uses the first transmissionformat, and thereby can transmit uplink control information having alarger amount of information than uplink control information (which maybe the HARQ control information) that can be transmitted using thesecond transmission format.

For example, the mobile station apparatus 200 uses the firsttransmission format to transmit, to the base station apparatus 100, theHARQ control information for a plurality of PDCCHs and/or a plurality ofdownlink transport blocks transmitted on each of DCC1, DCC2 and DCC3.Here, for example, the mobile station apparatus 200 uses the secondtransmission format to transmit, to the base station apparatus 100, theHARQ control information for one PDCCH and/or one downlink transportblock transmitted on DCC2. In other words, it is possible to increasethe number of information bits per sub-frame that can be transmittedusing the first transmission format as compared with the number ofinformation bits per sub-frame that can be transmitted using the secondtransmission format.

The mobile station apparatus 200 can apply, to the uplink controlinformation (which may be the HARQ control information) transmittedusing the first transmission format, for a modulation scheme that has ahigher modulation level than a modulation scheme which is applied to theuplink control information transmitted using the second transmissionformat.

For example, the mobile station apparatus 200 uses the firsttransmission format and applies to the uplink control information for 8Phase Shift Keying (8PSK) or Quadrature Amplitude Modulation (QAM), andtransmit the information to the base station apparatus 100. Here, forexample, the mobile station apparatus 200 uses the second transmissionformat and applies to the uplink control information for Binary PhaseShift Keying (BPSK) or Quadrature Phase Shift Keying (QPSK), andtransmit the information to the base station apparatus 100. In otherwords, it is possible to apply, to the uplink control informationtransmitted using the first transmission format, for a modulation schemehaving a higher modulation level than a modulation scheme which isapplied to the uplink information transmitted using the secondtransmission format. In other words, it is possible to increase theamount of information per symbol that can be transmitted using the firsttransmission format as compared with the amount of information persymbol that can be transmitted using the second transmission format.

The mobile station apparatus 200 can configure (generate), in differentmethods, an orthogonal resource of the PUCCH transmitted using the firsttransmission format (PUCCH where the uplink control information (whichmay be the HARQ control information) transmitted using the firsttransmission format is mapped) and an orthogonal resource of the PUCCHtransmitted using the second transmission format (PUCCH where the uplinkcontrol information transmitted using the second transmission format ismapped).

Here, the base station apparatus 100 may specify, for the mobile stationapparatus 200, method of configuring (method of generating) theorthogonal resource of the PUCCH transmitted using the firsttransmission format and the orthogonal resource of the PUCCH transmittedusing the second transmission format. In other words, it is possible toconfigure, in different methods, the orthogonal resource of the PUCCHtransmitted using the first transmission format and the orthogonalresource of the PUCCH transmitted using the second transmission format.

FIG. 5 is a diagram conceptually showing a configuration example of theorthogonal resource of the PUCCH used in case that the mobile stationapparatus 200 transmits the uplink control information. FIG. 5 shows, asa configuration example of the orthogonal resource, a cyclic shift of aCAZAC sequence in a horizontal direction (shows a cyclic shift of aCAZAC sequence represented by numbers from 1 to 12).

For example, the mobile station apparatus 200 uses the orthogonalresource (orthogonal resource which is indicated by being blackened andin which the number of the cyclic shifts of the CAZAC sequence is three)of the PUCCH to transmit the uplink control information. In other words,the mobile station apparatus 200 can perform, on the PUCCH, the cyclicshift of the CAZAC sequence in a frequency direction to therebyorthogonalize the resource, and can use the orthogonalized resource totransmit the uplink control information.

Likewise, FIG. 6 is a diagram conceptually showing a configurationexample of the orthogonal resource of the PUCCH used in case that themobile station apparatus 200 transmits the uplink control information.FIG. 6 shows, as a configuration example of the orthogonal resource, anindex of an orthogonal sequence (orthogonal symbol) in a verticaldirection (shows the index of the orthogonal sequence represented bynumbers from 1 to 5).

For example, the mobile station apparatus 200 uses the orthogonalresource (orthogonal resource which is indicated by being blackened andin which the index of the orthogonal sequence is two) to transmit theuplink control information. In other words, the mobile station apparatus200 can perform, on the PUCCH, the orthogonal sequence in a timedirection to thereby orthogonalize the resource, and can use theorthogonalized resource to transmit the uplink control information.

Likewise, FIG. 7 is a diagram conceptually showing a configurationexample of the orthogonal resource of the PUCCH used in case that themobile station apparatus 200 transmits the uplink control information.FIG. 7 shows, as a configuration example of the orthogonal resource, thecyclic shift of the CAZAC sequence in the horizontal direction and theindex of the orthogonal sequence in the vertical direction (shows thecyclic shift of the CAZAC sequence represented by numbers from 1 to 12and the index of the orthogonal sequence represented by numbers from 1to 4).

For example, the mobile station apparatus 200 uses the orthogonalresource (orthogonal resource which is indicated by being blackened andin which the number of the cyclic shifts of the CAZAC sequence is threeand the index of the orthogonal sequence is two) of the PUCCH totransmit the uplink control information. In other words, the mobilestation apparatus 200 can perform, on the PUCCH, the cyclic shift of theCAZAC sequence in the frequency direction and the orthogonal sequence inthe time direction to thereby orthogonalize the resource, and can usethe orthogonalized resource to transmit the uplink control information.

In FIG. 4, the mobile station apparatus 200 uses the first transmissionformat or the second transmission format in the orthogonal resource ofthe PUCCH configured by the configuration method described above totransmit the uplink control information (which may be the HARQ controlinformation) to the base station apparatus 100.

For example, the mobile station apparatus 200 can use the firsttransmission format in the orthogonal resource of the PUCCH configuredwith the orthogonal sequence shown in FIG. 6 to transmit the uplinkcontrol information. For example, the mobile station apparatus 200 canuse the second transmission format in the orthogonal resource of thePUCCH configured with the cyclic shift of the CAZAC sequence and theorthogonal sequence shown in FIG. 7 to transmit the uplink controlinformation.

Here, in the mobile communication system, the number of resources thatcan be orthogonalized is associated with the number of mobile stationapparatuses 200 that can transmit information in a certain timing (thenumber of mobile station apparatuses 200 that can be multiplexed). Forexample, when, as shown in FIG. 5, the cyclic shift of the CAZACsequence in the orthogonal resource is 12, it is possible to multiplexup to 12 mobile station apparatuses 200. Likewise, for example, when, asshown in FIG. 6, the index of the orthogonal sequence in the orthogonalresource is five, it is possible to multiplex up to 5 mobile stationapparatuses 200. Likewise, for example, when, as shown in FIG. 7, thecyclic shift of the CAZAC sequence in the orthogonal resource is 12 andthe index of the orthogonal sequence is 4, it is possible to multiplexup to 48 (12×4) mobile station apparatuses 200.

The base station apparatus 100 gives, within a cell to be controlled,consideration to the conditions of the downlink resource and the uplinkresource, the number of mobile station apparatuses 200 that performcommunication using a plurality of component carriers, the number ofmobile station apparatuses 200 that perform communication using onecomponent carrier and the like, and thus the mobile station apparatus200 can specify the method of configuring the orthogonal resource of thefirst transmission format and/or the second transmission format in whichthe uplink control information is transmitted.

Here, as described above, the base station apparatus 100 can alsotransmit information indicating the orthogonal resource as the firstparameter specifying the first region where the mobile station apparatus200 can utilize the PUCCH and the second parameter specifying the secondregion where the mobile station apparatus 200 can utilize the PUCCH. Thebase station apparatus 100 can also transmit information indicating theorthogonal resource as the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format and the second parameter specifying the secondregion where the mobile station apparatus 200 can utilize the secondtransmission format.

For example, the base station apparatus 100 transmits, as the firstparameter and the second parameter, information indicating the number ofcyclic shifts of the CAZAC sequence and information indicating the indexof the orthogonal sequence to the mobile station apparatus 200. The basestation apparatus 100 transmits, as the first parameter and the secondparameter, information indicating the number of cyclic shifts of theCAZAC sequence and information indicating the index of the orthogonalsequence, and thus the mobile station apparatus 200 can more flexiblyspecify the resource for transmitting the uplink control information.

For example, the base station apparatus 100 can specify, as the firstregion where the PUCCH can be utilized, the regions of up to number 3 ofthe cyclic shift of the CAZAC sequence. For example, the base stationapparatus 100 can specify, as the first region where the PUCCH can beutilized, the regions of up to number 2 of the index of the orthogonalsequence. For example, the base station apparatus 100 can specify, asthe first region where the PUCCH can be utilized, the regions of up tonumber 3 of the cyclic shift of the CAZAC sequence and of up to number 2of the index of the orthogonal sequence.

Furthermore, the mobile station apparatus 200 can use, as the firsttransmission format, a transmission format in which the HARQ controlinformation and the CQI can be transmitted together (simultaneously). Inother words, the mobile station apparatus 200 can use the firsttransmission format to transmit the HARQ control information and the CQItogether. For example, the mobile station apparatus 200 transmits theHARQ control information and the CQI together, the HARQ controlinformation is for the PDCCH and/or the downlink transport blocktransmitted on the PDSCH on each of DCC1, DCC2 and DCC3. The mobilestation apparatus 200 uses, as the first transmission format, thetransmission format in which the HARQ control information and the CQIcan be transmitted together, and thereby can use the PUCCH allocated bythe base station apparatus 100 more efficiently to transmit the uplinkcontrol information (the HARQ control information and the CQI).

Moreover, the mobile station apparatus 200 can use, as the firsttransmission format, a transmission format in which the HARQ controlinformation and the scheduling request can be transmitted together(simultaneously). In other words, the mobile station apparatus 200 canuse the first transmission format to transmit the HARQ controlinformation and the scheduling request. For example, the mobile stationapparatus 200 transmits the HARQ control information and the schedulingrequest, the HARQ control information is for the PDCCH and/or thedownlink transport block transmitted on the PDSCH on each of DCC1, DCC2and DCC3. The mobile station apparatus 200 uses, as the firsttransmission format, the transmission format in which the HARQ controlinformation and the scheduling request can be transmitted together, andthereby can use the PUCCH allocated by the base station apparatus 100more efficiently to transmit the uplink control information (the HARQcontrol information and the scheduling request).

As described above, in the first embodiment, the base station apparatus100 specifies the first region and the second region where the mobilestation apparatus 200 can utilize the PUCCH, and the mobile stationapparatus 200 uses the first region or the second region based on thePDCCH to which the base station apparatus 100 allocates (schedules) thePDSCH to transmit the HARQ control information. The base stationapparatus 100 and the mobile station apparatus 200 transmit and receive,as described above, the HARQ control information, and thus can transmitand receive the HARQ control information while using the uplink resourceefficiently.

For example, the mobile station apparatus 200 that communicates with thebase station apparatus 100 using a plurality of component carriers usesthe PUCCH in the first region specified by the base station apparatus100 to transmit the HARQ control information for a plurality of PDCCHsand/or a plurality of downlink transport blocks, and thereby cantransmit the HARQ control information while using the uplink resourceefficiently.

In case that the base station apparatus 100 uses one PDCCH on thespecific component carrier to allocate one PDSCH, the mobile stationapparatus 200 uses the second region to transmit the HARQ controlinformation, and thus it is possible to transmit and receive the HARQcontrol information at least on the specific component carrier betweenthe base station apparatus 100 and the mobile station apparatus 200.

For example, in conditions in which the number of component carriersused for communication differs between the base station apparatus 100and the mobile station apparatus 200 (for example, the base stationapparatus 100 is determined to perform communication using five DCCs andthe mobile station apparatus 200 is determined to perform communicationusing three DCCs), it is possible to transmit and receive the HARQcontrol information at least on the specific component carrier andthereby continue the communication between the base station apparatus100 and the mobile station apparatus 200.

In the base station apparatus 100, the first parameter specifying thefirst region and the second parameter specifying the second region aretransmitted to the mobile station apparatus 200, and thus it is possibleto specify each of the regions based on the conditions within themanaged cell (the number of mobile station apparatuses 200 performingcommunication using the downlink resource and the uplink resource and aplurality of component carriers, the number of mobile stationapparatuses 200 performing communication using one component carrier andthe like), with the result that it is possible to more flexibly controlthe transmission of the HARQ control information.

The mobile station apparatus 200 communicating with the base stationapparatus 100 using a plurality of component carriers uses the firsttransmission format to transmit the HARQ control information for aplurality of PDCCHs and/or a plurality of downlink transport blocks, andthereby can control the transmission of the HARQ control informationwhile using the uplink resource efficiently.

The mobile station apparatus 200 uses the first transmission format andthe second transmission format to transmit the HARQ control information,and thus it is possible to more flexibly control the transmission of theHARQ control information in the base station apparatus 100. In otherwords, it is possible to control, with the base station apparatus 100,the transmission of the HARQ control information with considerationgiven to the amount of information on the HARQ control informationtransmitted by the mobile station apparatus 200, the number of mobilestation apparatuses 200 transmitting the HARQ control information in acertain timing and the like.

Second Embodiment

A second embodiment of the present invention will now be described. Inthe second embodiment, the base station apparatus 100 transmits, to themobile station apparatus 200, the first parameter specifying the firstregion where the mobile station apparatus 200 can utilize the PUCCH andtransmits, to the mobile station apparatus 200, the second parameterspecifying the second region that is different from the first regionwhere the mobile station apparatus 200 can utilize the PUCCH; in casethat the base station apparatus 100 uses a plurality of PDCCHs toallocate (schedule) a plurality of PDSCHs in the same sub-frame, themobile station apparatus 200 uses the first region to transmit the HARQcontrol information to the base station apparatus 100 whereas, in casethat the base station apparatus 100 uses one PDCCH to allocate(schedule) one PDSCH, the mobile station apparatus 200 uses the firstregion or the second region to transmit the HARQ control information tothe base station apparatus 100.

The base station apparatus 100 transmits, to the mobile stationapparatus 200, the first parameter specifying the first region where themobile station apparatus 200 can utilize the PUCCH and transmits, to themobile station apparatus 200, the second parameter specifying the secondregion that is different from the first region where the mobile stationapparatus 200 can utilize the PUCCH; in case that the base stationapparatus 100 uses one PDCCH on the specific component carrier toallocate (schedule) one PDSCH on a component carrier different from thecomponent carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the first region to transmit the HARQ controlinformation to the base station apparatus 100 whereas, in case that thebase station apparatus 100 uses one PDCCH on the specific componentcarrier to allocate (schedule) one PDSCH on the same component carrieras the component carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the second region to transmit the HARQ controlinformation to the base station apparatus 100.

The base station apparatus 100 transmits, to the mobile stationapparatus 200, the first parameter specifying the first region where themobile station apparatus 200 can utilize the PUCCH and transmits, to themobile station apparatus 200, the second parameter specifying the secondregion that is different from the first region where the mobile stationapparatus 200 can utilize the PUCCH; in case that the base stationapparatus 100 uses a plurality of PDCCHs to allocate (schedule) aplurality of PDSCHs in the same sub-frame or in case that the basestation apparatus 100 uses one PDCCH on the specific component carrierto allocate (schedule) one PDSCH on a component carrier different fromthe component carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the first region to transmit the HARQ controlinformation to the base station apparatus 100 whereas, in case that thebase station apparatus 100 uses one PDCCH on the specific componentcarrier to allocate (schedule) one PDSCH on the same component carrieras the component carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the second region to transmit the HARQ controlinformation to the base station apparatus 100.

Furthermore, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,the second parameter specifying the second region in which the mobilestation apparatus 200 can utilize the second transmission format andwhich is different from the first region; in case that the base stationapparatus 100 uses a plurality of PDCCHs to allocate (schedule) aplurality of PDSCHs in the same sub-frame, the mobile station apparatus200 uses the first transmission format to transmit the HARQ controlinformation to the base station apparatus 100 whereas, in case that thebase station apparatus 100 uses one PDCCH to allocate (schedule) onePDSCH, the mobile station apparatus 200 uses the first transmissionformat or the second transmission format to transmit the HARQ controlinformation to the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,the second parameter specifying the second region different from thefirst region where the mobile station apparatus 200 can utilize thefirst transmission format; in case that the base station apparatus 100uses one PDCCH on the specific component carrier to allocate (schedule)one PDSCH on a component carrier different from the component carrierwhere the PDCCH is mapped, the mobile station apparatus 200 uses thefirst transmission format to transmit the HARQ control information tothe base station apparatus 100 whereas, in case that the base stationapparatus 100 uses one PDCCH on the specific component carrier toallocate (schedule) one PDSCH on the same component carrier as thecomponent carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the second transmission format to transmit the HARQcontrol information to the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,the second parameter specifying the second region in which the mobilestation apparatus 200 can utilize the second transmission format andwhich is different from the first region; in case that the base stationapparatus 100 uses a plurality of PDCCHs to allocate (schedule) aplurality of PDSCHs in the same sub-frame or in case that the basestation apparatus 100 uses one PDCCH on the specific component carrierto allocate (schedule) one PDSCH on a component carrier different fromthe component carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the first transmission format to transmit the HARQcontrol information to the base station apparatus 100 whereas, in casethat the base station apparatus 100 uses one PDCCH on the specificcomponent carrier to allocate (schedule) one PDSCH on the same componentcarrier as the component carrier where the PDCCH is mapped, the mobilestation apparatus 200 uses the second transmission format to transmitthe HARQ control information to the base station apparatus 100.

Here, the HARQ control information transmitted from the mobile stationapparatus 200 includes information indicating ACK/NACK and/orinformation indicating the DTX for the PDCCH and/or the downlinktransport block transmitted from the base station apparatus 100. Theinformation indicating the DTX is information which indicates that themobile station apparatus 200 has failed to detect the PDCCH transmittedfrom the base station apparatus 100.

Since the first parameter and the second parameter transmitted from thebase station apparatus 100 to the mobile station apparatus 200 are thesame as those described in the first embodiment, their description willnot be repeated.

As in the first embodiment, the second embodiment will be described withreference to FIG. 4. As in the first embodiment, the second embodimentcan be applied to any of the symmetrically carrier-aggregated andasymmetrically carrier-aggregated mobile communication systems.

In FIG. 4, the mobile station apparatus 200 uses the PUCCH allocated bythe base station apparatus 100 to transmit the HARQ control informationto the base station apparatus 100.

Here, in case that the base station apparatus 100 uses a plurality ofPDCCHs to allocate a plurality of PDSCHs in the same sub-frame, themobile station apparatus 200 uses the first region to transmit the HARQcontrol information. Here, the mobile station apparatus 200 uses theregion A (region A represented by RB1 and RB2) to transmit, for example,the CSI or the CQI to the base station apparatus 100.

For example, in FIG. 4, in case that the base station apparatus 100 usesthe PDCCHs on each of DCC1, DCC2 and DCC3 to allocate three PDSCHs inthe same sub-frame, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information. For example, in casethat the base station apparatus 100 uses two PDCCHs on DCC2 to allocatetwo PDSCHs in the same sub-frame, the mobile station apparatus 200 usesthe first region to transmit the HARQ control information.

In FIG. 4, in case that the base station apparatus 100 uses one PDSCH toallocate one PDSCH, the mobile station apparatus 200 uses the firstregion or the second region to transmit the HARQ control information.

Here, in case that the base station apparatus 100 uses one PDCCH on thespecific component carrier to allocate one PDSCH on a component carrierdifferent from the component carrier where the PDCCH is mapped, themobile station apparatus 200 uses the first region to transmit the HARQcontrol information. In case that the base station apparatus 100 usesone PDCCH on the specific component carrier to allocate one PDSCH on thesame component carrier as the component carrier where the PDCCH ismapped, the mobile station apparatus 200 uses the second region totransmit the HARQ control information.

As described in the first embodiment, the base station apparatus 100 canset the specific downlink component carrier for the mobile stationapparatus 200. The base station apparatus 100 and the mobile stationapparatus 200 can consider that the downlink component carriercorresponding to the uplink component carrier set, by the base stationapparatus 100, as the uplink component carrier on which the HARQ controlinformation is transmitted is the specific downlink component carrier.The base station apparatus 100 and the mobile station apparatus 200 canalso consider that the downlink component carrier used for performingthe initial connection establishment is the specific downlink componentcarrier.

For example, in FIG. 4, in case that the base station apparatus 100 usesthe broadcast channel to set DCC2 as the specific downlink componentcarrier and uses one PDCCH on DCC2 to allocate one PDSCH on DCC1 orDCC3, the mobile station apparatus 200 uses the first region to transmitthe HARQ control information. For example, incase that the base stationapparatus 100 uses the RRC signaling to set DCC2 as the specificdownlink component carrier and uses one PDCCH on DCC2 to allocate onePDSCH on DCC1 or DCC3, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information.

For example, in case that the base station apparatus 100 uses thebroadcast channel to set DCC2 as the specific downlink component carrierand uses one PDCCH on DCC2 to allocate one PDSCH on DCC2, the mobilestation apparatus 200 uses the second region to transmit the HARQcontrol information. For example, in case that the base stationapparatus 100 uses the RRC signaling to set DCC2 as the specificdownlink component carrier and uses one PDCCH on DCC2 to allocate onePDSCH on DCC2, the mobile station apparatus 200 uses the second regionto transmit the HARQ control information.

Here, incase that the base station apparatus 100 uses a plurality ofPDCCHs on the specific downlink component carrier to allocate aplurality of PDSCHs in the same sub-frame, the mobile station apparatus200 uses the first region to transmit the HARQ control information.

In other words, the mobile station apparatus 200 uses the first regionto transmit, to the base station apparatus 100, the HARQ controlinformation for a plurality of PDCCHs and/or the downlink transportblocks transmitted on a plurality of PDSCHs. The mobile stationapparatus 200 uses the first region to transmit, to the base stationapparatus 100, the HARQ control information for one PDCCH on thespecific component carrier and/or the downlink transport blocktransmitted on one PDSCH on a component carrier different from thecomponent carrier where the PDCCH is mapped.

In other words, in case that the base station apparatus uses a pluralityof PDCCHs to allocate a plurality of PDSCHs in the same sub-frame or incase that the base station apparatus uses one PDCCH on the specificcomponent carrier to allocate one PDSCH on a component carrier differentfrom the component carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the first region to transmit the HARQ controlinformation.

The mobile station apparatus 200 uses the second region to transmit, tothe base station apparatus 100, the HARQ control information for onePDCCH on the specific component carrier and/or the downlink transportblock transmitted on one PDSCH on the same component carrier as thecomponent carrier where the PDCCH is mapped.

Here, as described in the first embodiment, the mobile station apparatus200, in case of transmitting the HARQ control information by using thefirst region, uses the first transmission format to transmit the HARQcontrol information to the base station apparatus 100. The mobilestation apparatus 200, in case of transmitting the HARQ controlinformation by using the second region, uses the second transmissionformat to transmit the HARQ control information to the base stationapparatus 100.

In other words, in case that the base station apparatus 100 uses aplurality of PDCCHs to allocate a plurality of PDSCHs in the samesub-frame, the mobile station apparatus 200 uses the first transmissionformat to transmit the HARQ control information. In case that the basestation apparatus 100 uses one PDCCH to allocate one PDSCH, the mobilestation apparatus 200 uses the first transmission format or the secondtransmission format to transmit the HARQ control information.

In case that the base station apparatus 100 uses one PDCCH on thespecific component carrier to allocate one PDSCH on a component carrierdifferent from the component carrier where the PDCCH is mapped, themobile station apparatus 200 uses the first transmission format totransmit the HARQ control information. In other words, in case that thebase station apparatus 100 uses a plurality of PDCCHs to allocate aplurality of PDSCHs in the same sub-frame or in case that the basestation apparatus 100 uses one PDCCH on the specific component carrierto allocate one PDSCH on a component carrier different from thecomponent carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the first transmission format to transmit the HARQcontrol information.

In case that the base station apparatus 100 uses one PDCCH on thespecific component carrier to allocate one PDSCH on the same componentcarrier as the component carrier where the PDCCH is mapped, the mobilestation apparatus 200 uses the second transmission format to transmitthe HARQ control information.

Here, since the first transmission format and the second transmissionformat are the same as those described in the first embodiment, theirdescription will not be repeated.

As described above, in the second embodiment, the base station apparatus100 specifies the first region and the second region where the mobilestation apparatus 200 can utilize the PUCCH, and the mobile stationapparatus 200 uses the first region or the second region based on thePDCCH to which the base station apparatus 100 allocates (schedules) thePDSCH to transmit the HARQ control information. The base stationapparatus 100 and the mobile station apparatus 200 transmit and receive,as described above, the HARQ control information, and thus it ispossible to transmit and receive the HARQ control information whileusing the uplink resource efficiently.

For example, the mobile station apparatus 200 that communicates with thebase station apparatus 100 using a plurality of component carriers usesthe PUCCH in the first region specified by the base station apparatus100 to transmit the HARQ control information for a plurality of PDCCHsand/or a plurality of downlink transport blocks, and thus it is possibleto transmit the HARQ control information while using the uplink resourceefficiently.

In case that the base station apparatus 100 uses one PDCCH on thespecific component carrier to allocate one PDSCH on the same componentcarrier as the component carrier where the PDCCH is mapped, the mobilestation apparatus 200 uses the second region to transmit the HARQcontrol information, and thus it is possible to transmit and receive theHARQ control information at least on the specific component carrierbetween the base station apparatus 100 and the mobile station apparatus200.

For example, in conditions in which the number of component carriersused for communication differs between the base station apparatus 100and the mobile station apparatus 200 (for example, the base stationapparatus 100 is determined to perform communication using five DCCs andthe mobile station apparatus 200 is determined to perform communicationusing three DCCs), it is possible to transmit and receive the HARQcontrol information at least on the specific component carrier andthereby continue the communication between the base station apparatus100 and the mobile station apparatus 200.

In the base station apparatus 100, the first parameter specifying thefirst region and the second parameter specifying the second region aretransmitted to the mobile station apparatus, and thus it is possible tospecify each of the regions according to the conditions within themanaged cell (the number of mobile station apparatuses 200 performingcommunication using the downlink resource and the uplink resource and aplurality of component carriers, the number of mobile stationapparatuses 200 performing communication using one component carrier andthe like), with the result that it is possible to more flexibly controlthe transmission of the HARQ control information.

The mobile station apparatus 200 communicating with the base stationapparatus 100 using a plurality of component carriers uses the firsttransmission format to transmit the HARQ control information for aplurality of PDCCHs and/or a plurality of downlink transport blocks, andthus it is possible to control the transmission of the HARQ controlinformation while using the uplink resource efficiently.

The mobile station apparatus 200 uses the first transmission format andthe second transmission format to transmit the HARQ control information,and thus it is possible to more flexibly control, by the base stationapparatus 100, the transmission of the HARQ control information. Inother words, it is possible to control, by the base station apparatus100, the transmission of the HARQ control information with considerationgiven to the amount of information on the HARQ control informationtransmitted by the mobile station apparatus 200, the number of mobilestation apparatuses 200 transmitting the HARQ control information in acertain timing and the like.

Third Embodiment

A third embodiment of the present invention will now be described. Inthe third embodiment, the base station apparatus 100 transmits, to themobile station apparatus 200, the first parameter specifying the firstregion where the mobile station apparatus 200 can utilize the PUCCH andtransmits, to the mobile station apparatus 200, a plurality ofparameters specifying a plurality of regions that are different from thefirst region where the mobile station apparatus 200 can utilize thePUCCH; in case that the base station apparatus 100 uses a plurality ofPDCCHs to allocate (schedule) a plurality of PDSCHs in the samesub-frame, the mobile station apparatus 200 uses the first region totransmit the HARQ control information to the base station apparatus 100whereas, in case that the base station apparatus 100 uses one PDCCH toallocate (schedule) one PDSCH, the mobile station apparatus 200 useseither the first region or a plurality of regions to transmit the HARQcontrol information to the base station apparatus 100.

The base station apparatus 100 transmits, to the mobile stationapparatus 200, the first parameter specifying the first region where themobile station apparatus 200 can utilize the PUCCH and transmits, to themobile station apparatus 200, a plurality of parameters specifying aplurality of regions that are different from the first region where themobile station apparatus 200 can utilize the PUCCH; in case that thebase station apparatus 100 uses one PDCCH to allocate one PDSCH on acomponent carrier different from the component carrier where the PDCCHis mapped, the mobile station apparatus 200 uses the first region totransmit the HARQ control information to the base station apparatus 100whereas, in case that the base station apparatus 100 uses one PDCCH toallocate one PDSCH on the same component carrier as the componentcarrier where the PDCCH is mapped, the mobile station apparatus 200 usesany of the plurality of regions to transmit the HARQ control informationto the base station apparatus 100.

The base station apparatus 100 transmits, to the mobile stationapparatus 200, the first parameter specifying the first region where themobile station apparatus 200 can utilize the PUCCH and transmits, to themobile station apparatus 200, a plurality of parameters specifying aplurality of regions that are different from the first region where themobile station apparatus 200 can utilize the PUCCH; in case that thebase station apparatus 100 uses a plurality of PDCCHs to allocate(schedule) a plurality of PDCCHs in the same sub-frame or in case thatthe base station apparatus 100 uses one PDCCH to allocate one PDSCH on acomponent carrier different from the component carrier where the PDCCHis mapped, the mobile station apparatus 200 uses the first region totransmit the HARQ control information to the base station apparatus 100whereas, in case that the base station apparatus 100 uses one PDCCH toallocate one PDSCH on the same component carrier as the componentcarrier where the PDCCH is mapped, the mobile station apparatus 200 usesany of the plurality of regions to transmit the HARQ control informationto the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,a plurality of parameters specifying a plurality of regions in which themobile station apparatus 200 can utilize the second transmission formatand which are different from the first region; in case that the basestation apparatus 100 uses a plurality of PDCCHs to allocate (schedule)a plurality of PDSCHs in the same sub-frame, the mobile stationapparatus 200 uses the first transmission format to transmit the HARQcontrol information to the base station apparatus 100 whereas, in casethat the base station apparatus 100 uses one PDCCH to allocate(schedule) one PDSCH, the mobile station apparatus 200 uses the firsttransmission format or the second transmission format to transmit theHARQ control information to the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,a plurality of parameters specifying a plurality of regions in which themobile station apparatus 200 can utilize the second transmission formatand which are different from the first region; in case that the basestation apparatus 100 uses one PDCCH to allocate one PDSCH on acomponent carrier different from the component carrier where the PDCCHis mapped, the mobile station apparatus 200 uses the first transmissionformat to transmit the HARQ control information to the base stationapparatus 100 whereas, in case that the base station apparatus 100 usesone PDCCH to allocate one PDSCH on the same component carrier as thecomponent carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the second transmission format to transmit the HARQcontrol information to the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,a plurality of parameters specifying a plurality of regions in which themobile station apparatus 200 can utilize the second transmission formatand which are different from the first region; in case that the basestation apparatus 100 uses a plurality of PDCCHs to allocate (schedule)a plurality of PDSCHs in the same sub-frame or in case that the basestation apparatus 100 uses one PDCCH to allocate one PDSCH on acomponent carrier different from the component carrier where the PDCCHis mapped, the mobile station apparatus 200 uses the first transmissionformat to transmit the HARQ control information to the base stationapparatus 100 whereas, in case that the base station apparatus 100 usesone PDCCH to allocate one PDSCH on the same component carrier as thecomponent carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the second transmission format to transmit the HARQcontrol information to the base station apparatus 100. Here, the HARQcontrol information transmitted from the mobile station apparatus 200includes information indicating ACK/NACK and/or information indicatingthe DTX for the PDCCH and/or the downlink transport block transmittedfrom the base station apparatus 100. The information indicating the DTXis information which indicates that the mobile station apparatus 200 hasfailed to detect the PDCCH transmitted from the base station apparatus100.

FIG. 8 is a diagram showing an example of a mobile communication systemto which the third embodiment can be applied. FIG. 8 shows an enlargedpart of FIG. 9 and FIG. 10 for ease of illustration of the thirdembodiment. That is, the third embodiment can be applied to any of thesymmetrically carrier-aggregated and asymmetrically carrier-aggregatedmobile communication systems. In the following description, as anexample, only component carriers in the enlarged part will be discussed;needless to say, the same embodiment can be applied to all the componentcarriers.

FIG. 8 shows, as an example of the description of the third embodiment,three downlink component carriers (DCC1, DCC2 and DCC3). FIG. 8 alsoshows three uplink component carriers (UCC1, UCC2 and UCC3). In FIG. 8,as described in the first embodiment, the base station apparatus 100 andthe mobile station apparatus 200 perform downlink/uplink communicationusing the PDCCH, the PDSCH, the PUSCH, the PUCCH and the like.

In FIG. 8, regions that are extended with dotted lines from the PUCCH(PUCCH resource region indicated by a dotted pattern) on UCC1, the PUCCH(PUCCH resource region indicated by horizontal lines) on UCC2 and thePUCCH (PUCCH resource region indicated by vertical lines) on UCC3conceptually show the PUCCHs on UCC1, UCC2 and UCC3. Here, for ease ofdescription, the horizontal direction is assumed to be a frequencyresource (which may be represented as a bandwidth), and the orthogonalresource described above is not discussed.

As described in the first embodiment, the base station apparatus 100transmits the first parameter specifying the first region (region Bindicated by RB3 to RB5) where the mobile station apparatus 200 canutilize the PUCCH. Likewise, the base station apparatus 100 transmitsthe second parameter specifying the second region (region D-1 indicatedby RB6 and RB7) where the mobile station apparatus 200 can utilize thePUCCH. Likewise, the base station apparatus 100 transmits the thirdparameter specifying the third region (region D-2 indicated by RB8 andRB9) where the mobile station apparatus 200 can utilize the PUCCH.Likewise, the base station apparatus 100 transmits the fourth parameterspecifying the fourth region (region D-3 indicated by RB10 and RB11)where the mobile station apparatus 200 can utilize the PUCCH.

Here, although, in FIG. 8, as an example, the base station apparatus 100specifies up to the fourth region for the mobile station apparatus 200,the number of regions specified by the base station apparatus 100 variesaccording to the number of downlink component carriers used by the basestation apparatus 100 and the mobile station apparatus 200 forcommunication.

As described in the first embodiment, the base station apparatus 100 canset the uplink component carrier on which the mobile station apparatus200 transmits the HARQ control information. In FIG. 8, the base stationapparatus 100 sets UCC1 as the uplink component carrier on which themobile station apparatus 200 transmits the HARQ control information.

As described in the first embodiment, the base station apparatus 100allocates, to the mobile station apparatus 200, the PUCCH on which themobile station apparatus 200 transmits the HARQ control information. Themobile station apparatus 200 uses the PUCCH allocated by the basestation apparatus 100 to transmit the HARQ control information to thebase station apparatus 100.

Here, in FIG. 8, in case that the base station apparatus 100 uses aplurality of PDCCHs to allocate a plurality of PDSCHs in the samesub-frame, the mobile station apparatus 200 uses the first region totransmit the HARQ control information. Here, the mobile stationapparatus 200 uses the region A (region A represented by RB1 and RB2) totransmit, for example, the CSI or the CQI to the base station apparatus100.

For example, in FIG. 8, in case that the base station apparatus 100 usesthe PDCCHs on each of DCC1, DCC2 and DCC3 to allocate three PDSCHs inthe same sub-frame, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information. For example, in casethat the base station apparatus 100 uses two PDCCHs on DCC2 to allocatetwo PDSCHs in the same sub-frame, the mobile station apparatus 200 usesthe first region to transmit the HARQ control information.

In case that the base station apparatus 100 uses one PDCCH to allocateone PDSCH, the mobile station apparatus 200 uses the first region or aplurality of regions to transmit the HARQ control information.

Here, in case that the base station apparatus 100 uses one PDCCH toallocate one PDSCH on a component carrier different from the componentcarrier where the PDCCH is mapped, the mobile station apparatus 200 usesthe first region to transmit the HARQ control information. In case thatthe base station apparatus 100 uses one PDCCH to allocate one PDSCH onthe same component carrier as the component carrier where the PDCCH ismapped, the mobile station apparatus 200 uses any of a plurality ofregions (the second region, the third region or the fourth region) totransmit the HARQ control information to the base station apparatus 100.

For example, in FIG. 8, in case that the base station apparatus 100 usesone PDCCH on DCC1 to allocate one PDSCH on DCC2 or DCC3, the mobilestation apparatus 200 uses the first region to transmit the HARQ controlinformation. For example, in case that the base station apparatus 100uses one PDCCH on DCC2 to allocate one PDSCH on DCC1 or DCC3, the mobilestation apparatus 200 uses the first region to transmit the HARQ controlinformation. For example, in case that the base station apparatus 100uses one PDCCH on DCC3 to allocate one PDSCH on DCC1 or DCC2, the mobilestation apparatus 200 uses the first region to transmit the HARQ controlinformation.

For example, in case that the base station apparatus 100 uses one PDCCHon DCC1 to allocate one PDSCH on DCC1, the mobile station apparatus 200uses the second region (any of a plurality of regions) to transmit theHARQ control information. For example, in case that the base stationapparatus 100 uses one PDCCH on DCC2 to allocate one PDSCH on DCC2, themobile station apparatus 200 uses the third region (any of a pluralityof regions) to transmit the HARQ control information. For example, incase that the base station apparatus 100 uses one PDCCH on DCC3 toallocate one PDSCH on DCC3, the mobile station apparatus 200 uses thefourth region (any of a plurality of regions) to transmit the HARQcontrol information.

Here, as described in the first embodiment, the base station apparatus100 can associate the downlink component carrier with the uplinkcomponent carrier. In FIG. 8, the base station apparatus 100 associatesDCC1 with UCC1, DCC2 with UCC2 and DCC3 with UCC3. In other words, themobile station apparatus 200 transmits the HARQ control information tothe base station apparatus 100 in the region of the PUCCH on the uplinkcomponent carrier corresponding to the downlink component carrier.

In other words, in FIG. 8, the mobile station apparatus 200 uses theregion (second region) of the PUCCH on UCC1 corresponding to DCC1 totransmit the HARQ control information for the PDCCH and/or the downlinktransport block transmitted on DCC1. The mobile station apparatus 200uses the region (third region) of the PUCCH on DCC2 corresponding toDCC2 to transmit the HARQ control information for the PDCCH and/or thedownlink transport block transmitted on DCC2. The mobile stationapparatus 200 uses the region (fourth region) of the PUCCH on UCC3corresponding to DCC3 to transmit the HARQ control information for thePDCCH and/or the downlink transport block transmitted on DCC3.

In other words, the mobile station apparatus 200 uses the first regionto transmit, to the base station apparatus 100, the HARQ controlinformation for a plurality of PDSCHs and/or the downlink transportblocks transmitted on a plurality of PDSCHs. The mobile stationapparatus 200 uses the first region to transmit, to the base stationapparatus 100, the HARQ control information for one PDCCH and/or thedownlink transport block transmitted on one PDSCH on a component carrierdifferent from the component carrier where one PDCCH is mapped.

In other words, in case that the base station apparatus 100 uses aplurality of PDCCHs to allocate a plurality of PDSCHs in the samesub-frame or in case that the base station apparatus 100 uses one PDCCHto allocate one PDSCH on a component carrier different from thecomponent carrier where the PDCCH is mapped, the mobile stationapparatus 200 uses the first region to transmit the HARQ controlinformation.

The mobile station apparatus 200 uses any of a plurality of regions totransmit, to the base station apparatus 100, the HARQ controlinformation for one PDCCH and/or the downlink transport blocktransmitted on one PDSCH on the same component carrier as the componentcarrier where one PDCCH is mapped.

Here, in FIG. 8, the mobile station apparatus 200, in case oftransmitting the HARQ control information by using the first region,uses the first transmission format to transmit the HARQ controlinformation to the base station apparatus 100. In case that the mobilestation apparatus 200 uses any of a plurality of regions to transmit theHARQ control information, the mobile station apparatus 200 uses thesecond transmission format to transmit the HARQ control information tothe base station apparatus 100.

In other words, in case that the base station apparatus 100 uses aplurality of PDCCHs to allocate a plurality of PDSCHs in the samesub-frame, the mobile station apparatus 200 uses the first transmissionformat to transmit the HARQ control information. In case that the basestation apparatus 100 uses one PDCCH to allocate one PDSCH, the mobilestation apparatus 200 uses the first transmission format or the secondtransmission format to transmit the HARQ control information.

In case that the base station apparatus 100 uses one PDCCH to allocateone PDSCH on a component carrier different from the component carrierwhere the PDCCH is mapped, the mobile station apparatus 200 uses thefirst transmission format to transmit the HARQ control information tothe base station apparatus 100. In other words, in case that the basestation apparatus 100 uses a plurality of PDCCHs to allocate a pluralityof PDSCHs in the same sub-frame or in case that the base stationapparatus 100 uses one PDCCH to allocate one PDSCH on a componentcarrier different from the component carrier where the PDCCH is mapped,the mobile station apparatus 200 uses the first transmission format totransmit the HARQ control information to the base station apparatus 100.

In case that the base station apparatus 100 uses one PDCCH to allocateone PDSCH on the same component carrier as the component carrier wherethe PDCCH is mapped, the mobile station apparatus 200 uses the secondtransmission format to transmit the HARQ control information to the basestation apparatus 100.

Here, since the first transmission format and the second transmissionformat are the same as those described in the first embodiment, theirdescription will not be repeated.

As described above, in the third embodiment, the base station apparatus100 specifies the first region and a plurality of regions where themobile station apparatus 200 can utilize the PUCCH, and the mobilestation apparatus 200 uses either the first region or the plurality ofregions based on the PDCCH to which the base station apparatus 100allocates (schedules) the PDSCH to transmit the HARQ controlinformation. The base station apparatus 100 and the mobile stationapparatus 200 transmit and receive, as described above, the HARQ controlinformation, and thus it is possible to transmit and receive the HARQcontrol information while using the uplink resource efficiently.

For example, the mobile station apparatus 200 that communicates with thebase station apparatus 100 using a plurality of component carriers usesthe PUCCH in the first region specified by the base station apparatus100 to transmit the HARQ control information for a plurality of PDCCHsand/or a plurality of downlink transport blocks, and thus it is possibleto transmit the HARQ control information while using the uplink resourceefficiently.

In case that the base station apparatus 100 uses one PDCCH to allocateone PDSCH on the same component carrier as the component carrier wherethe PDCCH is mapped, the mobile station apparatus 200 uses any of aplurality of regions to transmit the HARQ control information, and thusit is possible to transmit and receive the HARQ control information atleast on one component carrier (each of the component carriers) betweenthe base station apparatus 100 and the mobile station apparatus 200.

For example, in conditions in which the number of component carriersused for communication differs between the base station apparatus 100and the mobile station apparatus 200 (for example, the base stationapparatus 100 is determined to perform communication using five DCCs andthe mobile station apparatus 200 is determined to perform communicationusing three DCCs), it is possible to transmit and receive the HARQcontrol information at least on one component carrier (each of thecomponent carriers) and thereby continue the communication between thebase station apparatus 100 and the mobile station apparatus 200.

In the base station apparatus 100, the first parameter specifying thefirst region and a plurality of parameters specifying a plurality ofregions are transmitted to the mobile station apparatus, and thus it ispossible to specify each of the regions according to the conditionswithin the managed cell (the number of mobile station apparatuses 200performing communication using the downlink resource and the uplinkresource and a plurality of component carriers, the number of mobilestation apparatuses 200 performing communication using one componentcarrier and the like), with the result that it is possible to moreflexibly control the transmission of the HARQ control information.

The mobile station apparatus 200 communicating with the base stationapparatus 100 using a plurality of component carriers transmits, withthe first transmission format, the HARQ control information for aplurality of PDCCHs and/or a plurality of downlink transport blocks, andthus it is possible to control the transmission of the HARQ controlinformation while using the uplink resource efficiently.

The mobile station apparatus 200 uses the first transmission format andthe second transmission format to transmit the HARQ control information,and thus it is possible to more flexibly control, by the base stationapparatus 100, the transmission of the HARQ control information. Inother words, it is possible to control, by the base station apparatus100, the transmission of the HARQ control information with considerationgiven to the amount of information on the HARQ control informationtransmitted by the mobile station apparatus 200, the number of mobilestation apparatuses 200 transmitting the HARQ control information in acertain timing and the like.

Fourth Embodiment

A fourth embodiment of the present invention will now be described. Inthe fourth embodiment, the base station apparatus 100 transmits, to themobile station apparatus 200, the first parameter specifying the firstregion where the mobile station apparatus 200 can utilize the PUCCH andtransmits, to the mobile station apparatus 200, a plurality ofparameters specifying a plurality of parameter that are different fromthe first region where the mobile station apparatus 200 can utilize thePUCCH; in case that the base station apparatus 100 uses a plurality ofPDCCHs to allocate (schedule) a plurality of PDSCHs in the samesub-frame, the mobile station apparatus 200 uses the first region totransmit the HARQ control information to the base station apparatus 100whereas, in case that the base station apparatus 100 uses one PDCCH toallocate (schedule) one PDSCH, the mobile station apparatus 200 useseither the first region or a plurality of regions to transmit the HARQcontrol information to the base station apparatus 100.

The base station apparatus 100 transmits, to the mobile stationapparatus 200, the first parameter specifying the first region where themobile station apparatus 200 can utilize the PUCCH and transmits, to themobile station apparatus 200, a plurality of parameters specifying aplurality of regions that are different from the first region where themobile station apparatus 200 can utilize the PUCCH; in case that thebase station apparatus 100 uses one PDCCH carrying a component carrierindicator field to allocate one PDSCH, the mobile station apparatus 200uses the first region to transmit the HARQ control information to thebase station apparatus 100 whereas, in case that the base stationapparatus 100 uses one PDCCH not carrying the component carrierindicator field to allocate (schedule) one PDSCH, the mobile stationapparatus 200 uses any of a plurality of regions to transmit the HARQcontrol information to the base station apparatus 100.

The base station apparatus 100 transmits, to the mobile stationapparatus 200, the first parameter specifying the first region where themobile station apparatus 200 can utilize the PUCCH and transmits, to themobile station apparatus 200, a plurality of parameters specifying aplurality of regions that are different from the first region where themobile station apparatus 200 can utilize the PUCCH; in case that thebase station apparatus 100 uses a plurality of PDCCHs to allocate(schedule) a plurality of PDSCHs in the same sub-frame or in case thatthe base station apparatus 100 uses one PDCCH carrying the componentcarrier indicator field to allocate (schedule) one PDSCH, the mobilestation apparatus 200 uses the first region to transmit the HARQ controlinformation to the base station apparatus 100 whereas, in case that thebase station apparatus 100 uses one PDCCH not carrying the componentcarrier indicator field to allocate (schedule) one PDSCH, the mobilestation apparatus 200 uses any of a plurality of regions to transmit theHARQ control information to the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,a plurality of parameters specifying a plurality of regions in which themobile station apparatus 200 can utilize the second transmission formatand which are different from the first region; in case that the basestation apparatus 100 uses a plurality of PDCCHs to allocate (schedule)a plurality of PDCCHs in the same sub-frame, the mobile stationapparatus 200 uses the first transmission format to transmit the HARQcontrol information to the base station apparatus 100 whereas, in casethat the base station apparatus 100 uses one PDCCH to allocate(schedule) one PDSCH, the mobile station apparatus 200 uses the firsttransmission format or the second transmission format to transmit theHARQ control information to the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,a plurality of parameters specifying a plurality of regions in which themobile station apparatus 200 can utilize the second transmission formatand which are different from the first region; in case that the basestation apparatus 100 uses one PDCCH carrying the component carrierindicator field to allocate (schedule) one PDSCH, the mobile stationapparatus 200 uses the first transmission format to transmit the HARQcontrol information to the base station apparatus 100 whereas, incasethat the base station apparatus 100 uses one PDCCH not carrying thecomponent carrier indicator field to allocate (schedule) one PDSCH, themobile station apparatus 200 uses the second transmission format totransmit the HARQ control information to the base station apparatus 100.

Moreover, the base station apparatus 100 transmits, to the mobilestation apparatus 200, the first parameter specifying the first regionwhere the mobile station apparatus 200 can utilize the firsttransmission format, and transmits, to the mobile station apparatus 200,a plurality of parameters specifying a plurality of regions in which themobile station apparatus 200 can utilize the second transmission formatand which are different from the first region; in case that the basestation apparatus 100 uses a plurality of PDCCHs to allocate (schedule)a plurality of PDSCHs in the same sub-frame or in case that the basestation apparatus 100 uses one PDCCH carrying the component carrierindicator field to allocate (schedule) one PDSCH, the mobile stationapparatus 200 uses the first transmission format to transmit the HARQcontrol information to the base station apparatus 100 whereas, in casethat the base station apparatus 100 uses one PDCCH not carrying thecomponent carrier indicator field to allocate (schedule) one PDSCH, themobile station apparatus 200 uses the second transmission format totransmit the HARQ control information to the base station apparatus 100.

Here, the HARQ control information transmitted from the mobile stationapparatus 200 includes information indicating ACK/NACK and/orinformation indicating the DTX for the PDCCH and/or the downlinktransport block transmitted from the base station apparatus 100. Theinformation indicating the DTX is information which indicates that themobile station apparatus 200 has failed to detect the PDCCH transmittedfrom the base station apparatus 100.

Since the first parameter and a plurality of parameters transmitted fromthe base station apparatus 100 to the mobile station apparatus 200 arethe same as described in the third embodiment, their description willnot be repeated.

As in the third embodiment, the fourth embodiment will be described withreference to FIG. 8. As in the third embodiment, the fourth embodimentcan be applied to any of the symmetrically carrier-aggregated andasymmetrically carrier-aggregated mobile communication systems.

In FIG. 8, the mobile station apparatus 200 uses the PUCCH allocated bythe base station apparatus 100, and transmits the HARQ controlinformation to the base station apparatus 100.

Here, in case that the base station apparatus 100 uses a plurality ofPDCCHs to allocate a plurality of PDSCHs in the same sub-frame, themobile station apparatus 200 uses the first region to transmit the HARQcontrol information. Here, the mobile station apparatus 200 uses theregion A (region A represented by RB1 and RB2), and transmits, forexample, the CSI or the CQI to the base station apparatus 100.

For example, in FIG. 8, in case that the base station apparatus 100 usesthe PDCCHs on each of DCC1, DCC2 and DCC3 to allocate three PDSCHs inthe same sub-frame, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information. For example, in casethat the base station apparatus 100 uses two PDCCHs on DCC2 to allocatetwo PDSCHs in the same sub-frame, the mobile station apparatus 200 usesthe first region to transmit the HARQ control information.

In case that the base station apparatus 100 uses one PDCCH to allocateone PDSCH, the mobile station apparatus 200 uses either the first regionor a plurality of regions to transmit the HARQ control information.

In case that the base station apparatus 100 uses one PDCCH carrying thecomponent carrier indicator field to allocate one PDSCH, the mobilestation apparatus 200 uses the first region to transmit the HARQ controlinformation to the base station apparatus 100. In case that the basestation apparatus 100 uses one PDCCH not carrying the component carrierindicator field to allocate one PDSCH, the mobile station apparatus 200uses any of a plurality of regions (the second region, the third regionor the fourth region) to transmit the HARQ control information.

As described above, the base station apparatus 100 transmits thecomponent carrier indicator field on the PDCCH, and can therebyallocate, to the mobile station apparatus 200, the PDSCH on the samecomponent carrier as or a different component carrier from the componentcarrier where the PDCCH is mapped. The base station apparatus 100 canset, for each of the component carriers, in each of the mobile stationapparatuses 200, information indicating whether or not the componentcarrier indicator field is transmitted on the PDCCH.

For example, in FIG. 8, in case that the base station apparatus 100 usesone PDCCH carrying the component carrier indicator field on DCC1 toallocate one PDSCH, the mobile station apparatus 200 uses the firstregion to transmit the HARQ control information. For example, in casethat the base station apparatus 100 uses one PDCCH carrying thecomponent carrier indicator field on DCC2 to allocate one PDSCH, themobile station apparatus 200 uses the first region to transmit the HARQcontrol information. For example, in case that the base stationapparatus 100 uses one PDCCH carrying the component carrier indicatorfield on DCC3 to allocate one PDSCH, the mobile station apparatus 200uses the first region to transmit the HARQ control information.

For example, in case that the base station apparatus 100 uses one PDCCHnot carrying the component carrier indicator field on DCC1 to allocateone PDSCH on DCC1, the mobile station apparatus 200 uses the secondregion (any of a plurality of regions) to transmit the HARQ controlinformation. For example, in case that the base station apparatus 100uses one PDCCH not carrying the component carrier indicator field onDCC2 to allocate one PDSCH on DCC2, the mobile station apparatus 200uses the third region (any of a plurality of regions) to transmit theHARQ control information. For example, in case that the base stationapparatus 100 uses one PDCCH not carrying the component carrierindicator field on DCC3 to allocate one PDSCH on DCC3, the mobilestation apparatus 200 uses the fourth region (any of a plurality ofregions) to transmit the HARQ control information.

Here, the base station apparatus 100 cannot allocate, with one PDCCH notcarrying the component carrier indicator field, one PDSCH on a componentcarrier different from the component carrier where the PDCCH is mapped.

Here, as described in the first embodiment, the base station apparatus100 can associate the downlink component carrier with the uplinkcomponent carrier. In FIG. 8, the base station apparatus 100 associatesDCC1 with UCC1, DCC2 with UCC2 and DCC3 with UCC3. In other words, themobile station apparatus 200 transmits the HARQ control information tothe base station apparatus 100 in the region of the PUCCH on the uplinkcomponent carrier corresponding to the downlink component carrier.

In other words, the mobile station apparatus 200 uses the first region,and transmits, to the base station apparatus 100, the HARQ controlinformation for a plurality of PDSCHs and/or the downlink transportblocks transmitted on a plurality of PDCCHs. The mobile stationapparatus 200 uses the first region, and transmits, to the base stationapparatus 100, the HARQ control information for one PDCCH carrying thecomponent carrier indicator field and/or the downlink transport blocktransmitted on one PDSCH.

In other words, in case that the base station apparatus 100 uses aplurality of PDCCHs to allocate a plurality of PDSCHs in the samesub-frame or in case that the base station apparatus 100 uses one PDCCHcarrying the component carrier indicator field to allocate one PDSCH,the mobile station apparatus 200 uses the first region to transmit theHARQ control information.

The mobile station apparatus 200 uses any of a plurality of regions, andtransmits, to the base station apparatus 100, the HARQ controlinformation for one PDCCH not carrying the component carrier indicatorfield and/or the downlink transport block transmitted on one PDSCH.

Here, in FIG. 8, in case that the mobile station apparatus 200 uses thefirst region to transmit the HARQ control information, the mobilestation apparatus 200 uses the first transmission format to transmit theHARQ control information to the base station apparatus 100. In case thatthe mobile station apparatus 200 uses any of a plurality of regions totransmit the HARQ control information, the mobile station apparatus 200uses the second transmission format to transmit the HARQ controlinformation to the base station apparatus 100.

In other words, in case that the base station apparatus 100 uses aplurality of PDCCHs to allocate a plurality of PDSCHs in the samesub-frame, the mobile station apparatus 200 uses the first transmissionformat to transmit the HARQ control information. In case that the basestation apparatus 100 uses one PDCCH to allocate one PDSCH, the mobilestation apparatus 200 uses the first transmission format or the secondtransmission format to transmit the HARQ control information.

In case that the base station apparatus 100 uses one PDCCH carrying thecomponent carrier indicator field to allocate one PDSCH, the mobilestation apparatus 200 uses the first transmission format to transmit theHARQ control information to the base station apparatus 100. In otherwords, in case that the base station apparatus 100 uses a plurality ofPDCCHs to allocate a plurality of PDSCHs in the same sub-frame or incase that the base station apparatus 100 uses one PDCCH carrying thecomponent carrier indicator field to allocate one PDSCH, the mobilestation apparatus 200 uses the first transmission format to transmit theHARQ control information to the base station apparatus 100.

In case that the base station apparatus 100 uses one PDCCH not carryingthe component carrier indicator field to allocate one PDSCH, the mobilestation apparatus 200 uses the second transmission format to transmitthe HARQ control information to the base station apparatus 100.

Here, since the first transmission format and the second transmissionformat are the same as those described in the first embodiment, theirdescription will not be repeated.

As described above, in the fourth embodiment, the base station apparatus100 specifies the first region and a plurality of regions where themobile station apparatus 200 can utilize the PUCCH, and the mobilestation apparatus 200 uses either the first region or a plurality ofregions based on the PDCCH to which the base station apparatus 100allocates (schedules) the PDSCH, and transmits the HARQ controlinformation. The base station apparatus 100 and the mobile stationapparatus 200 transmit and receive, as described above, the HARQ controlinformation, and thus it is possible to transmit and receive the HARQcontrol information while using the uplink resource efficiently.

For example, the mobile station apparatus 200 that communicates with thebase station apparatus 100 using a plurality of component carriers usesthe PUCCH in the first region specified by the base station apparatus100 and thereby transmits the HARQ control information for a pluralityof PDCCHs and/or a plurality of downlink transport blocks, and thus itis possible to transmit the HARQ control information while using theuplink resource efficiently.

In case that the base station apparatus 100 uses one PDCCH not carryingthe component carrier indicator field to allocate one PDSCH, the mobilestation apparatus 200 uses any of a plurality of regions to transmit theHARQ control information, and thus it is possible to transmit andreceive the HARQ control information, in the component carrier where thePDCCH not carrying the component carrier indicator field is transmitted,between the base station apparatus 100 and the mobile station apparatus200.

For example, in conditions in which the number of component carriersused for communication differs between the base station apparatus 100and the mobile station apparatus 200 (for example, the base stationapparatus 100 is determined to perform communication using five DCCs andthe mobile station apparatus 200 is determined to perform communicationusing three DCCs), it is possible to transmit and receive the HARQcontrol information in the component carrier where the PDCCH notcarrying the component carrier indicator field is transmitted, andthereby continue the communication between the base station apparatus100 and the mobile station apparatus 200.

In the base station apparatus 100, the first parameter specifying thefirst region and a plurality of parameters specifying a plurality ofregions are transmitted to the mobile station apparatus, and thus it ispossible to specify each of the regions according to the conditionswithin the managed cell (the number of mobile station apparatuses 200performing communication using the downlink resource and the uplinkresource and a plurality of component carriers, the number of mobilestation apparatuses 200 performing communication using one componentcarrier and the like), with the result that it is possible to moreflexibly control the transmission of the HARQ control information.

The mobile station apparatus 200 communicating with the base stationapparatus 100 using a plurality of component carriers transmits, withthe first transmission format, the HARQ control information for aplurality of PDCCHs and/or a plurality of downlink transport blocks, andthus it is possible to control the transmission of the HARQ controlinformation while using the uplink resource efficiently.

The mobile station apparatus 200 uses the first transmission format andthe second transmission format to transmit the HARQ control information,and thus it is possible to more flexibly control, by the base stationapparatus 100, the transmission of the HARQ control information. Inother words, it is possible to control, by the base station apparatus100, the transmission of the HARQ control information with considerationgiven to the amount of information on the HARQ control informationtransmitted by the mobile station apparatus 200, the number of mobilestation apparatuses 200 transmitting the HARQ control information in acertain timing and the like.

As described above, the mobile communication system of the presentinvention is a mobile communication system in which the base stationapparatus and mobile station apparatus use a plurality of componentcarriers to communicate with each other, and in which the base stationapparatus transmits, to the mobile station apparatus, the firstparameter specifying the first region where the mobile station apparatuscan utilize the physical uplink control channel and transmits, to themobile station apparatus, the second parameter specifying the secondregion in which the mobile station apparatus can utilize the physicaluplink control channel and which is different from the first region; incase that the base station apparatus uses a plurality of physicaldownlink control channels to allocate a plurality of physical downlinkshared channels in the same sub-frame, the mobile station apparatus usesthe first region to transmit the HARQ control information to the basestation apparatus whereas, in case that the base station apparatus usesone physical downlink control channel to allocate one physical downlinkshared channel, the mobile station apparatus uses the first region orthe second region to transmit the HARQ control information to the basestation apparatus.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, the second parameter specifying the second region inwhich the mobile station apparatus can utilize the physical uplinkcontrol channel and which is different from the first region; in casethat the base station apparatus uses one physical downlink controlchannel on a component carrier other than a specific component carrierto allocate one physical downlink shared channel, the mobile stationapparatus uses the first region to transmit the HARQ control informationto the base station apparatus whereas, in case that the base stationapparatus uses one physical downlink control channel on a componentcarrier other than the specific component carrier to allocate onephysical downlink shared channel, the mobile station apparatus uses thesecond region to transmit the HARQ control information to the basestation apparatus.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, the second parameter specifying the second region inwhich the mobile station apparatus can utilize the physical uplinkcontrol channel and which is different from the first region; in casethat the base station apparatus uses a plurality of physical downlinkcontrol channels to allocate a plurality of physical downlink sharedchannels in the same sub-frame or in case that the base stationapparatus uses one physical downlink control channel on a componentcarrier other than the specific component carrier to allocate onephysical downlink shared channel, the mobile station apparatus uses thefirst region to transmit the HARQ control information to the basestation apparatus whereas, in case that the base station apparatus usesone physical downlink control channel on a component carrier other thanthe specific component carrier to allocate one physical downlink sharedchannel, the mobile station apparatus uses the second region to transmitthe HARQ control information to the base station apparatus.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, the second parameter specifying the second region inwhich the mobile station apparatus can utilize the physical uplinkcontrol channel and which is different from the first region; in casethat the base station apparatus uses one physical downlink controlchannel on the specific component carrier to allocate one physicaldownlink shared channel on a component carrier different from thecomponent carrier where the physical downlink control channel is mapped,the mobile station apparatus uses the first region to transmit the HARQcontrol information to the base station apparatus whereas, in case thatthe base station apparatus uses one physical downlink control channel onthe specific component carrier to allocate one physical downlink sharedchannel on the same component carrier as the component carrier where thephysical downlink control channel is mapped, the mobile stationapparatus uses the second region to transmit the HARQ controlinformation to the base station apparatus.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, the second parameter specifying the second region inwhich the mobile station apparatus can utilize the physical uplinkcontrol channel and which is different from the first region; in casethat the base station apparatus uses a plurality of physical downlinkcontrol channels to allocate a plurality of physical downlink sharedchannels in the same sub-frame or in case that the base stationapparatus uses one physical downlink control channel on the specificcomponent carrier to allocate one physical downlink shared channel on acomponent carrier different from the component carrier where thephysical downlink control channel is mapped, the mobile stationapparatus uses the first region to transmit the HARQ control informationto the base station apparatus whereas, in case that the base stationapparatus uses one physical downlink control channel on the specificcomponent carrier to allocate one physical downlink shared channel onthe same component carrier as the component carrier where the physicaldownlink control channel is mapped, the mobile station apparatus usesthe second region to transmit the HARQ control information to the basestation apparatus.

The mobile communication system uses, in the first region, the firsttransmission format to transmit the HARQ control information to the basestation apparatus, and uses, in the second region, the secondtransmission format to transmit the HARQ control information to the basestation apparatus; the first transmission format and the secondtransmission format are different from each other.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, a plurality of parameters specifying a plurality ofregions in which the mobile station apparatus can utilize the physicaluplink control channel and which is different from the first region; incase that the base station apparatus uses a plurality of physicaldownlink control channels to allocate a plurality of physical downlinkshared channels in the same sub-frame, the mobile station apparatus usesthe first region to transmit the HARQ control information to the basestation apparatus whereas, in case that the base station apparatus usesone physical downlink control channel to allocate one physical downlinkshared channel, the mobile station apparatus uses either the firstregion or a plurality of regions to transmit the HARQ controlinformation to the base station apparatus.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, a plurality of parameters specifying a plurality ofregions in which the mobile station apparatus can utilize the physicaluplink control channel and which is different from the first region; incase that the base station apparatus uses one physical downlink controlchannel to allocate one physical downlink shared channel on a componentcarrier different from the component carrier where the physical downlinkcontrol channel is mapped, the mobile station apparatus uses the firstregion to transmit the HARQ control information to the base stationapparatus whereas, in case that the base station apparatus uses onephysical downlink control channel to allocate one physical downlinkshared channel on a component carrier different from the componentcarrier where the physical downlink control channel is mapped, themobile station apparatus uses a plurality of regions to transmit theHARQ control information to the base station apparatus.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, a plurality of parameters specifying a plurality ofregions in which the mobile station apparatus can utilize the physicaluplink control channel and which is different from the first region; incase that the base station apparatus uses a plurality of physicaldownlink control channels to allocate a plurality of physical downlinkshared channels in the same sub-frame or in case that the base stationapparatus uses one physical downlink control channel to allocate onephysical downlink shared channel on a component carrier different fromthe component carrier where the physical downlink control channel ismapped, the mobile station apparatus uses the first region to transmitthe HARQ control information to the base station apparatus whereas, incase that the base station apparatus uses one physical downlink controlchannel to allocate one physical downlink shared channel on a componentcarrier different from the component carrier where the physical downlinkcontrol channel is mapped, the mobile station apparatus uses any of aplurality of regions to transmit the HARQ control information to thebase station apparatus.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, a plurality of parameters specifying a plurality ofregions in which the mobile station apparatus can utilize the physicaluplink control channel and which is different from the first region; incase that the base station apparatus uses one physical downlink controlchannel carrying the component carrier indicator field to allocate onephysical downlink shared channel, the mobile station apparatus uses thefirst region to transmit the HARQ control information to the basestation apparatus whereas, in case that the base station apparatus usesone physical downlink control channel not carrying the component carrierindicator field to allocate one physical downlink shared channel, themobile station apparatus uses any of a plurality of regions to transmitthe HARQ control information to the base station apparatus.

The mobile communication system of the present invention is also amobile communication system in which the base station apparatus andmobile station apparatus use a plurality of component carriers tocommunicate with each other, and in which the base station apparatustransmits, to the mobile station apparatus, the first parameterspecifying the first region where the mobile station apparatus canutilize the physical uplink control channel and transmits, to the mobilestation apparatus, a plurality of parameters specifying a plurality ofregions in which the mobile station apparatus can utilize the physicaluplink control channel and which is different from the first region; incase that the base station apparatus uses a plurality of physicaldownlink control channels to allocate a plurality of physical downlinkshared channels in the same sub-frame or in case that the base stationapparatus uses one physical downlink control channel carrying thecomponent carrier indicator field to allocate one physical downlinkshared channel, the mobile station apparatus uses the first region totransmit the HARQ control information to the base station apparatuswhereas, in case that the base station apparatus uses one physicaldownlink control channel not carrying the component carrier indicatorfield to allocate one physical downlink shared channel, the mobilestation apparatus uses any of a plurality of regions to transmit theHARQ control information to the base station apparatus.

The mobile communication system uses, in the first region, the firsttransmission format to transmit the HARQ control information to the basestation apparatus, and uses, in any of a plurality of regions, thesecond transmission format to transmit the HARQ control information tothe base station apparatus; the first transmission format and the secondtransmission format are different from each other.

The HARQ control information includes information which indicates ACK orNACK for the downlink transport block transmitted on the physicaldownlink shared channel.

The HARQ control information includes information which indicates thatthe mobile station apparatus has failed to detect the physical downlinkcontrol channel.

The base station apparatus in the mobile communication system in whichthe base station apparatus and the mobile station apparatus use aplurality of component carriers to communicate with each othertransmits, to the mobile station apparatus, the first parameterspecifying the first region where the physical uplink control channelcan be utilized and transmits, to the mobile station apparatus, thesecond parameter specifying the second region in which the physicaluplink control channel can be utilized and which is different from thefirst region; in case that the base station apparatus uses a pluralityof physical downlink control channels to allocate a plurality ofphysical downlink shared channels in the same sub-frame to the mobilestation apparatus, the base station apparatus uses the first region toreceive the HARQ control information from the mobile station apparatuswhereas, in case that the base station apparatus uses one physicaldownlink control channel to allocate one physical downlink sharedchannel to the mobile station apparatus, the base station apparatus usesthe first region or the second region to receive the HARQ controlinformation from the mobile station apparatus.

The base station apparatus in the mobile communication system in whichthe base station apparatus and the mobile station apparatus use aplurality of component carriers to communicate with each othertransmits, to the mobile station apparatus, the first parameterspecifying the first region where the physical uplink control channelcan be utilized and transmits, to the mobile station apparatus, thesecond parameter specifying the second region in which the physicaluplink control channel can be utilized and which is different from thefirst region; in case that the base station apparatus uses one physicaldownlink control channel on a component carrier other than the specificcomponent carrier to allocate one physical downlink shared channel tothe mobile station apparatus, the base station apparatus uses the firstregion to receive the HARQ control information from the mobile stationapparatus whereas, in case that the base station apparatus uses onephysical downlink control channel on the specific component carrier toallocate one physical downlink shared channel to the mobile stationapparatus, the base station apparatus uses the second region to receivethe HARQ control information from the mobile station apparatus.

The base station apparatus in the mobile communication system in whichthe base station apparatus and the mobile station apparatus use aplurality of component carriers to communicate with each othertransmits, to the mobile station apparatus, the first parameterspecifying the first region where the physical uplink control channelcan be utilized and transmits, to the mobile station apparatus, thesecond parameter specifying the second region in which the physicaluplink control channel can be utilized and which is different from thefirst region; in case that the base station apparatus uses a pluralityof physical downlink control channels to allocate a plurality ofphysical downlink shared channels in the sub-frame to the mobile stationapparatus or in case that the base station apparatus uses one physicaldownlink control channel on a component carrier other than the specificcomponent carrier to allocate one physical downlink shared channel tothe mobile station apparatus, the base station apparatus uses the firstregion to receive the HARQ control information from the mobile stationapparatus whereas, in case that the base station apparatus uses onephysical downlink control channel on the specific component carrier toallocate one physical downlink shared channel to the mobile stationapparatus, the base station apparatus uses the second region to receivethe HARQ control information from the mobile station apparatus.

The mobile station apparatus in the mobile communication system in whichthe base station apparatus and the mobile station apparatus use aplurality of component carriers to communicate with each other receives,from the base station apparatus, the first parameter specifying thefirst region where the physical uplink control channel can be utilizedand receives, from the base station apparatus, the second parameterspecifying the second region in which the physical uplink controlchannel can be utilized and which is different from the first region; incase that the base station apparatus uses a plurality of physicaldownlink control channels to allocate a plurality of physical downlinkshared channels in the same sub-frame, the mobile station apparatus usesthe first region to transmit the HARQ control information to the basestation apparatus whereas, in case that the base station apparatus usesone physical downlink control channel to allocate one physical downlinkshared channel, the mobile station apparatus uses the first region orthe second region to transmit the HARQ control information to the basestation apparatus.

The mobile station apparatus in the mobile communication system in whichthe base station apparatus and the mobile station apparatus use aplurality of component carriers to communicate with each other receives,from the base station apparatus, the first parameter specifying thefirst region where the physical uplink control channel can be utilizedand receives, from the base station apparatus, the second parameterspecifying the second region in which the mobile station apparatus canutilize the physical uplink control channel and which is different fromthe first region; in case that the base station apparatus uses onephysical downlink control channel on a component carrier other than thespecific component carrier to allocate one physical downlink sharedchannel, the mobile station apparatus uses the first region to transmitthe HARQ control information to the base station apparatus whereas, incase that the base station apparatus uses one physical downlink controlchannel on the specific component carrier to allocate one physicaldownlink shared channel, the mobile station apparatus uses the secondregion to transmit the HARQ control information to the base stationapparatus.

The mobile station apparatus in the mobile communication system in whichthe base station apparatus and the mobile station apparatus use aplurality of component carriers to communicate with each other receives,from the base station apparatus, the first parameter specifying thefirst region where a physical uplink control channel can be utilized andreceives, from the base station apparatus, the second parameterspecifying the second region which is different from the first region inwhich the mobile station apparatus can utilize the physical uplinkcontrol channel; in case that the base station apparatus uses aplurality of physical downlink control channels to allocate a pluralityof physical downlink shared channels in the same sub-frame or in casethat the base station apparatus uses one of the physical downlinkcontrol channels on a component carrier other than the specificcomponent carrier to allocate one of the physical downlink sharedchannels, the mobile station apparatus uses the first region to transmitthe HARQ control information to the base station apparatus whereas, incase that the base station apparatus uses one physical downlink controlchannel on the specific component carrier to allocate one physicaldownlink shared channel, the mobile station apparatus uses the secondregion to transmit the HARQ control information to the base stationapparatus.

In a communication method of the base station apparatus in which thebase station apparatus and the mobile station apparatus use a pluralityof component carriers to communicate with each other, the base stationapparatus transmits, to the mobile station apparatus, the firstparameter specifying the first region where the physical uplink controlchannel can be utilized, and transmits, to the mobile station apparatus,the second parameter specifying the second region in which the physicaluplink control channel can be utilized and which is different from thefirst region; in case that the base station apparatus uses a pluralityof physical downlink control channels to allocate a plurality ofphysical downlink shared channels in the same sub-frame to the mobilestation apparatus, the base station apparatus uses the first region toreceive the HARQ control information from the mobile station apparatuswhereas, in case that the base station apparatus uses one of thephysical downlink control channels to allocate one of the physicaldownlink shared channels to the mobile station apparatus, the basestation apparatus uses the first region or the second region to receivethe HARQ control information from the mobile station apparatus.

In a communication method of the base station apparatus in which thebase station apparatus and the mobile station apparatus use a pluralityof component carriers to communicate with each other, the base stationapparatus transmits, to the mobile station apparatus, the firstparameter specifying the first region where the physical uplink controlchannel can be utilized, and transmits, to the mobile station apparatus,the second parameter specifying the second region in which the physicaluplink control channel can be utilized and which is different from thefirst region; in case that the base station apparatus uses one physicaldownlink control channel on a component carrier other than the specificcomponent carrier to allocate one physical downlink shared channel tothe mobile station apparatus, the base station apparatus uses the firstregion to receive the HARQ control information from the mobile stationapparatus whereas, in case that the base station apparatus uses one ofthe physical downlink control channels on the specific component carrierto allocate one of the physical downlink shared channels to the mobilestation apparatus, the base station apparatus uses the second region toreceive the HARQ control information from the mobile station apparatus.

In a communication method of the base station apparatus in which thebase station apparatus and the mobile station apparatus use a pluralityof component carriers to communicate with each other, the base stationapparatus transmits, to the mobile station apparatus, the firstparameter specifying the first region where the physical uplink controlchannel can be utilized, and transmits, to the mobile station apparatus,the second parameter specifying the second region in which the physicaluplink control channel can be utilized and which is different from thefirst region; in case that the base station apparatus uses a pluralityof physical downlink control channels to allocate a plurality ofphysical downlink shared channels in the same sub-frame to the mobilestation apparatus or in case that the base station apparatus uses onephysical downlink control channel on a component carrier other than thespecific component carrier to allocate one physical downlink sharedchannel to the mobile station apparatus, the base station apparatus usesthe first region to receive the HARQ control information from the mobilestation apparatus whereas, in case that the base station apparatus usesone physical downlink control channel on the specific component carrierto allocate one physical downlink shared channel to the mobile stationapparatus, the base station apparatus uses the second region to receivethe HARQ control information from the mobile station apparatus.

In a communication method of the mobile station apparatus in which thebase station apparatus and the mobile station apparatus use a pluralityof component carriers to communicate with each other, the mobile stationapparatus receives, from the base station apparatus, the first parameterspecifying the first region where the physical uplink control channelcan be utilized, and receives, from the base station apparatus, thesecond parameter specifying the second region in which the physicaluplink control channel can be utilized and which is different from thefirst region; in case that the base station apparatus uses a pluralityof physical downlink control channels to allocate a plurality ofphysical downlink shared channels in the same sub-frame, the mobilestation apparatus uses the first region to transmit the HARQ controlinformation to the base station apparatus whereas, in case that the basestation apparatus uses one physical downlink control channel to allocateone physical downlink shared channel, the mobile station apparatus usesthe first region or the second region to transmit the HARQ controlinformation to the base station apparatus.

In a communication method of the mobile station apparatus in which thebase station apparatus and the mobile station apparatus use a pluralityof component carriers to communicate with each other, the mobile stationapparatus receives, from the base station apparatus, the first parameterspecifying the first region where the physical uplink control channelcan be utilized, and receives, from the base station apparatus, thesecond parameter specifying the second region in which the mobilestation apparatus can utilize the physical uplink control channel andwhich is different from the first region; in case that the base stationapparatus uses one physical downlink control channel on a componentcarrier other than the specific component carrier to allocate onephysical downlink shared channel, the mobile station apparatus uses thefirst region to transmit the HARQ control information to the basestation apparatus whereas, in case that the base station apparatus usesone physical downlink control channel on the specific component carrierto allocate one physical downlink shared channel, the mobile stationapparatus uses the second region to transmit the HARQ controlinformation to the base station apparatus.

In a communication method of the mobile station apparatus in which thebase station apparatus and the mobile station apparatus use a pluralityof component carriers to communicate with each other, the mobile stationapparatus receives, from the base station apparatus, the first parameterspecifying the first region where the physical uplink control channelcan be utilized, and receives, from the base station apparatus, thesecond parameter specifying the second region in which the mobilestation apparatus can utilize the physical uplink control channel andwhich is different from the first region; in case that the base stationapparatus uses a plurality of physical downlink control channels toallocate a plurality of physical downlink control channels in the samesub-frame or incase that the base station apparatus uses one of thephysical downlink control channels on a component carrier other than thespecific component carrier to allocate one of the physical downlinkshared channels, the mobile station apparatus uses the first region totransmit the HARQ control information to the base station apparatuswhereas, in case that the base station apparatus uses one of thephysical downlink control channels on the specific component carrier toallocate one of the physical downlink shared channels, the mobilestation apparatus uses the second region to transmit the HARQ controlinformation to the base station apparatus.

The embodiments described above can also be applied to an integratedcircuit incorporated in the base station apparatus 100 and the mobilestation apparatus 200. In the embodiments described above, the basestation apparatus 100 and the mobile station apparatus 200 may becontrolled by recording programs for realizing functions within the basestation apparatus 100 and functions within the mobile station apparatus200 in a computer readable recording medium, making a computer systemread the programs recorded in the recording medium and executing theprograms. The “computer system” described here includes hardware such asan OS and peripheral devices.

The “computer readable recording medium” refers to a portable mediumsuch as a flexible disc, a magneto-optical disc, a ROM or a CD-ROM or astorage device such as a hard disk incorporated in a computer system.Furthermore, the “computer readable recording medium” includes a medium,such as a communication line used when a program is transmitted througha network such as the Internet or a communication line such as atelephone line, that dynamically holds a program for a short period oftime and a medium, such as a volatile memory within a computer systemfunctioning as a server and a client in that case, that holds a programfor a given period of time. The program described above may be a programfor realizing part of the functions described above or may be a programthat combines with a program already recorded in a computer system andthereby can realize the functions described above.

Although the embodiments of the present invention have been described indetail with reference to the drawings, the specific configuration is notlimited to these embodiments; designs and the like without departingfrom the spirit of the present invention are included in the scope ofclaims.

-   -   100 base station apparatus    -   101 data control unit    -   102 transmission data modulation unit    -   103 radio unit    -   104 scheduling unit    -   105 channel estimation unit    -   106 received data demodulation unit    -   107 data extraction unit    -   108 higher layer    -   109 antenna    -   110 radio resource control unit    -   200 mobile station apparatus    -   201 data control unit    -   202 transmission data modulation unit    -   203 radio unit    -   204 scheduling unit    -   205 channel estimation unit    -   206 received data demodulation unit    -   207 data extraction unit    -   208 higher layer    -   209 antenna    -   210 radio resource control unit

1-48. (canceled)
 49. A mobile station apparatus which communicates with a base station apparatus using a plurality of component carriers, the mobile station apparatus comprising: a decoding unit which attempts to decode at least one physical downlink control channel on at least a first downlink component carrier; a transmitting unit which transmits, to the base station apparatus, Hybrid Automatic Repeat Request (HARQ) control information using a first physical uplink control channel resource in case that the physical downlink control channel corresponding to a physical downlink shared channel transmission on a second downlink component carrier other than the first downlink component carrier is detected; wherein the transmitting unit which transmits, to the base station apparatus, the HARQ control information using a second physical uplink control channel resource in case that only the physical downlink control channel corresponding to the physical downlink shared channel transmission on the first downlink component carrier is detected.
 50. The mobile station apparatus according to claim 49, wherein the transmitting unit which transmits, to the base station apparatus, the HARQ control information using the first physical uplink control channel resource in case that a plurality of physical downlink control channels corresponding to a plurality of physical downlink shared channels transmission is detected.
 51. The mobile station apparatus according to claim 49, wherein the first downlink component carrier is indicated by the base station apparatus using a radio resource control signal.
 52. The mobile station apparatus according to claim 49, wherein the first downlink component carrier is a downlink component carrier corresponding to an uplink component carrier on which the HARQ control information is transmitted using a physical uplink control channel.
 53. The mobile station apparatus according to claim 49, wherein the first downlink component carrier is a downlink component carrier on which the mobile station apparatus performs initial connection establishment.
 54. The mobile station apparatus according to claim 49, wherein the HARQ control information includes information indicating a positive acknowledgment or a negative acknowledgement for a downlink transport block.
 55. A base station apparatus which communicates with a mobile station apparatus using a plurality of component carriers, the base station apparatus comprising: a setting unit which sets, to the mobile station apparatus, at least one physical downlink control channel on at least a first downlink component carrier; a receiving unit which receives, from the mobile station apparatus, Hybrid Automatic Repeat Request (HARQ) control information using a first physical uplink control channel resource in case that the physical downlink control channel corresponding to a physical downlink shared channel transmission on a second downlink component carrier other than the first downlink component carrier is set; wherein the receiving unit which receives, from the mobile station apparatus, the HARQ control information using a second physical uplink control channel resource in case that only the physical downlink control channel corresponding to the physical downlink shared channel transmission on the first downlink component carrier is set.
 56. The base station apparatus according to claim 55, wherein the receiving unit which receives, from the mobile station apparatus, the HARQ control information using the first physical uplink control channel resource in case that a plurality of physical downlink control channels corresponding to a plurality of physical downlink shared channels transmission is set.
 57. The base station apparatus according to claim 55, wherein the first downlink component carrier is indicated by the base station apparatus using a radio resource control signal.
 58. The base station apparatus according to claim 55, wherein the first downlink component carrier is a downlink component carrier corresponding to an uplink component carrier on which the HARQ control information is transmitted using a physical uplink control channel.
 59. The base station apparatus according to claim 55, wherein the first downlink component carrier is a downlink component carrier on which the mobile station apparatus performs initial connection establishment.
 60. The base station apparatus according to claim 55, wherein the HARQ control information includes information indicating a positive acknowledgment or a negative acknowledgement for a downlink transport block.
 61. A communication method of a mobile station apparatus which communicates with a base station apparatus using a plurality of component carriers, the communication method comprising: attempting to decode at least one physical downlink control channel on at least a first downlink component carrier; transmitting, to the base station apparatus, Hybrid Automatic Repeat Request (HARQ) control information using a first physical uplink control channel resource in case that the physical downlink control channel corresponding to a physical downlink shared channel transmission on a second downlink component carrier other than the first downlink component carrier is detected; and transmitting, to the base station apparatus, the HARQ control information using a second physical uplink control channel resource in case that only the physical downlink control channel corresponding to the physical downlink shared channel transmission on the first downlink component carrier is detected.
 62. A communication method of a base station apparatus which communicates with a mobile station apparatus using a plurality of component carriers, the communication method characterized by comprising: setting, to the mobile station apparatus, at least one physical downlink control channel on at least a first downlink component carrier; receiving, from the mobile station apparatus, Hybrid Automatic Repeat Request (HARQ) control information using a first physical uplink control channel resource in case that the physical downlink control channel corresponding to a physical downlink shared channel transmission on a second downlink component carrier other than the first downlink component carrier is set; and receiving, from the mobile station apparatus, the HARQ control information using a second physical uplink control channel resource in case that only the physical downlink control channel corresponding to the physical downlink shared channel transmission on the first downlink component carrier is set.
 63. The mobile station apparatus according to claim 50, wherein the first downlink component carrier is indicated by the base station apparatus using a radio resource control signal.
 64. The mobile station apparatus according to claim 50, wherein the first downlink component carrier is a downlink component carrier corresponding to an uplink component carrier on which the HARQ control information is transmitted using a physical uplink control channel.
 65. The mobile station apparatus according to claim 50, wherein the first downlink component carrier is a downlink component carrier on which the mobile station apparatus performs initial connection establishment.
 66. The mobile station apparatus according to claim 50, wherein the HARQ control information includes information indicating a positive acknowledgment or a negative acknowledgement for a downlink transport block.
 67. The base station apparatus according to any of claims 56, wherein the first downlink component carrier is indicated by the base station apparatus using a radio resource control signal.
 68. The base station apparatus according to claim 56, wherein the first downlink component carrier is a downlink component carrier corresponding to an uplink component carrier on which the HARQ control information is transmitted using a physical uplink control channel. 